I think there's a case for two different sources: one external, the simple lack of any further low hanging fruit to exploit, and one internal, which is exactly this - the increasing inadequacy of our institutions to create the conditions for innovation, often caused paradoxically by the excessive focus on promoting innovation. "If scientists gave us all this cool stuff by working on their own, imagine how good they will be if we hire a lot more of them and pit them into a competition for funding with each other!" was a catastrophically stupid idea, assuming humans can be made to produce highly creative work on command and like clockwork. It led to short-termism, creating a humongous confusing, amorphous mass of tiny innovations, many of which non replicable or straight up bogus, and efficiently killing off any incentive to actually work on long term, solid, sweeping discoveries.
Some of those issues though are political, not technological. Albeit it can certainly be argued that one of the causes of stagnation is that it's the political and social institutions that have become inadequate at incentivising true innovation.
And what’s the matter with bits, anyway? Are they less important than atoms?
Arguably, yes, because they are less fundamental. A revolution in our understanding of the fundamental laws of physics begets more secondary revolutions down the line; quantum mechanics alone gave us lasers, nuclear power and those very bits - to name but a few. So from a revolution in our understanding of the world comes the promise of more revolutions once that reaches the application stage. Understanding quantum gravity might lead to warp drives. But no matter how great our ability to manipulate bits, the best they generally can do (except for the possibility of AGI, I guess) is help us squeeze more efficiency out of what we have already. We feel the energy problem especially keenly right now, of course, and far from helping all that much, computers only eat up ever more energy, sometimes in rather pointless ways. A clean, cheap source of energy right now would be worth far more than all the social media in the world.
The question is probably also one of tradeoffs though - where we exist right now may be a maximum of productivity, not so much of resilience. A single failure today could cascade a series of consequences that would be much deadlier than one in a world that produces less, but more reasonably distributed (and we know that there is food that gets wasted, so it's not like we have literally zero margin here, though of course waste itself can't be eliminated).
Things sometimes get bad. Once things get sufficiently bad that no one can deviate from short-term selfish actions or be a different type of person without being wiped out, things are no longer stable. People cheat on long term investments, including various combinations of things such as having and raising children, maintaining infrastructure and defending norms. The seed corn gets eaten. Eventually, usually when some random new threat inevitably emerges, the order collapses, and things start again. The rise and fall of civilizations.
Uneasily looks at CO2 concentration and global average temperatures graphs for the last decades
The problem is also that in this sense the interests of the civilisation - as a single entity - and the interests of the individuals inside can be dramatically misaligned. Shocks, well, tend to kill people in droves, and make others' lives miserable (while, arguably, in some cases, they probably also do make some lives better, if the fallen system was oppressive to them). Just like mass extinctions create biodiversity and reshuffle the genetic deck in the long term, but also kill a lot of living beings. So the hypothetical solution for the steady state future in which shocks aren't a thing any more - how do we just allow for some slack to exist anyway? - are relevant before it too, because they could be applied to give some ability to a civilisation to drift away from its path of pure optimisation, sacrificing productivity in the name of resilience and flexibility. Which might prevent those shocks in the first place, when they're caused by the civilisation's own stupid rigidity. If we're able to learn to do that, then we can do better now and do better in that future. If we can't, we're doomed to be at the mercy of catastrophes of our own creation now, and if we ever make it to that future at all (having survived the dangers of climate change, nuclear weapons, nanotechnology, AI, and who knows what else that we could totally turn on ourselves through that sort of sheer civilisation-wide single-mindedness), then we're doomed to fall prey to perfect optimisation and just do the same dull things forever. Which by the way is something I think we're worryingly seeing signs of in the political sphere. While we don't have the power to control the forces of nature, we do have increasingly more power to control other humans, and that power is being turned more and more towards enforcing homogeneity and paralysing change by those who hold it. See for example China's experiment in social scores and such. A people rising up in revolution - the political/human equivalent of a shock - is always less likely, because of both weapon technology and because of these methods of micromanagement of consensus and dissent. You could easily end up with perfectly stable technocratic or authoritarian governments that just do nothing except perpetuate themselves, bringing about another form of stasis that can only harm humanity long term.