I've done a fair bit of IFS from books. I found it to be a moderately useful lens for self-understanding. I don't completely buy its models of the mind, but taken as a fake framework, it's pretty decent at generating insights into one's mental structure and suggesting potential methods for change.
My one caution is that, of the people I know who have spent >hundreds of hours using IFS, there's a strong tendency to get into a loop of ruminating on childhood traumas in a way that seems unproductive to me. This is not unique to IFS, of course; maybe a third or half of introspection/therapy practices have this trait.
IMO it makes sense to spend between 5 and 50 hours trying out IFS, learn what you can, and then move on to other techniques.
Also the Curies, the Coris, the Durants, and others. What these all have in common is that they worked together on the same project. Offhand I can't think of any couples like this where both made historically-significant contributions to different projects.
Oh also, woman politicians in living memory seem much less likely to have kids than woman politicians "from history". I would guess this is a consequence of the shift away from explicitly hereditary political power rather than a consequence of feminism or the pill or anything, but it's hard to untangle different hypotheses because there were so few woman politicians between the advent of industrialization and recent rise from ~1970-1990.
At conservative estimates, I've looked into dozens of significant pre-industrial people, dozens of significant people between the Industrial Revolution and 1970, and >100 significant post-1970 people. Among historically significant people and leaders-of-fields who get articles and books written about them, there has not been any change in who has kids large enough to jump out at me, except that in the past ~20 years there have been somewhat more openly gay entrepreneurs in the West.
My impression from many, many biographies of ambitious and world-changing people is that historically significant politicians and entrepreneurs nearly always have kids, to such an overwhelming extent that >50% of exceptions are biologically infertile or are gay. Among historically significant scientists, engineers, and philosophers, most have kids, but it's not nearly so overpowering and I'm not immediately sure if it's different from what you'd expect of baseline "successful people".
Of course this is purely descriptive rather than mechanistic, but there's overwhelming mountains of data suggesting that world-changing impact is at least consistent with having kids, and in some fields, being the-sort-of-person-who-chooses-to-have-kids seems like it's nearly a prerequisite.
—Make More Land.
—American policing. There's tons of obvious problems with this, and the proposed solutions range from obvious and nearly universally agreed upon (reduce SWAT-style raids by >90%, end/drastically reform qualified immunity, abolish civil asset forfeiture, etc) to speculative and contentious. Such reforms generally don't match the incentives of the police themselves, and civil oversight is currently too diffuse and ineffective to impose reform. National authorities are incapable of any reform, and while a few state and cities have made small changes in the past year, the core issues will not be addressed anywhere in the near future.
—COVID vaccine distribution. Our society can reach better equilibria, as shown by the normal flu vaccine distribution and by the occasional stories where a freezer breaks down and all the shots are administered before they expire. Nevertheless our current system is a mess, no one feels they have responsibility for the mess, and there is no sign it will be fixed before the pandemic ends.
—Whatever made development of the F-35 fighter plane so much worse than the development of previous fighter planes.
—There are several cases in America (and presumably elsewhere, although I'm less familiar) where a relatively small, coordinated group successfully lobbies for laws which benefit themselves by imposing small costs on the country as a whole. Because the costs are so widely distributed, no one has a strong incentive to overturn these, and lawmakers have a moderate incentive to cooperate with the special interest group. The canonical examples include the artificial complexity of the tax code held in place by tax-preparation firms; ethanol subsidies supported by corn growers; and comically long copyright for artistic works, supported by media conglomerates (IIRC these expire 70 years after the death of the author!).
How do we distinguish between Inner Rings and Groups of Sound Craftsmen?
The essay's answer to this is solid, and has steered me well:
In any wholesome group of people which holds together for a good purpose, the exclusions are in a sense accidental. Three or four people who are together for the sake of some piece of work exclude others because there is work only for so many or because the others can’t in fact do it. Your little musical group limits its numbers because the rooms they meet in are only so big. But your genuine Inner Ring exists for exclusion. There’d be no fun if there were no outsiders. The invisible line would have no meaning unless most people were on the wrong side of it. Exclusion is no accident; it is the essence.
My own experience supports this being the crucial difference. I've encountered a few groups where the exclusion is the main purpose of the group, *and* the exclusion is based on reasonably good judgments of competence. These groups strike me as pathological and corrupting in the way that Lewis describes. I've also encountered many groups where exclusion is only "accidental", and also the people are very bad at judging competence. These groups certainly have their problems, but they don't have the particular issues that Lewis describes.
I've lived in both rationalist and non-rationalist group houses and observed a bunch more. In my experience, there are special upsides and downsides that come with ideological/subcultural group houses that you won't find in e.g. a house formed by a regular friend group or a bunch of people thrown together by Craigslist ads. Those features appear pretty similar whether the subculture is rationalists or animal rights activists or an artistic scene or whatever, and I've seen stories similar to the OP's from several different subcultures. I think communities like these are net positive overall and I expect I'll be living in group houses in the future, but some people absolutely do get burned and it's worth being especially careful because of how entangled the social scene is, even beyond the regular roommate issues.
What's worked for me isn't focusing on agency per se. I've had more success from focusing on my deeper desires (for which "agency" is often instrumental) and figuring out how to get them. Sometimes those plans run into psychological barriers. When that happens, I'll do whatever it takes to overcome or dissolve those barriers—rationality techniques, therapy techniques, pure willpower, esoteric philosophy, etc etc. After repeating this a bunch I ended up more proactive than before because there were fewer mental barriers between me and taking the "agenty" action when it happened to be a good idea.
Like, I wasn't thinking "I should be more agenty, I'll go [organize a speaker series | raise tens of thousands of dollars for weirdo projects | change my interpersonal demeanor | solve an intellectual problem that no one I know can answer] to practice agency." Rather, I found myself in situations where things like that were good ways to get what I wanted but I was too averse to actually do it, then wrestled with my soul until I could do it anyway. (Sometimes this step takes two hours, sometimes it takes six months.) Each step unlocked more of a general willingness to do similar things, not just the narrow ability to do that one thing.
Of the people I know who seriously follow an approach like this for at least a couple years, about 50% wind up notably more effective than their peers and about 10% wind up insane.