The first answer is that I think the stereotype of LWers who aren't agentic is out of date (the article you linked is 13 years old). Much of the time when I meet LWers they're running or key figures in ambitious projects, organizing useful events, or doing interesting research.
The second answer is that the way I meet these people is through reaching out to see if our projects have synergy, or them reaching out to me, or a mutual friend introducing us. Also going to conferences or workshops or meetups and doing the same.
A few times I've gone to Rationality or EA meetups and I'm one of the people with the most agency there. Usually I don't go back to those meetups, and I imagine there's an evaporative cooling effect where other who do things also don't go.
So the second answer is that the way to connect with people who do things is to do things - then you have something to connect about.