Ehn, it's definitely anecdotal (personal experience, etc.), but from what I've seen that actually ties back into the belief you can't do much. If you believe you have very little capacity to enact change, but still want to at least try, you pick small targets. You chip away at the superficial stuff -- get done what you (think you) can get done, in the hope it opens the path to larger changes. It's been a pretty consistent narrative, at least with the stuff that I've been involved in, that there is deeply seeded problems, but they're not something that can be directly addressed. Activists, or just people who want to make a positive change, simply don't have the capacity -- resources, social weight, whatever -- to have an effect. So you do what you can until (in the hope that) addressing the deeper issues becomes possible.
And the potential domino effect feeds back into that, to a degree. Since you're focusing small (because you think that's all you can manage), then your proverbial field of vision is fairly narrow. You don't expect you're going to make a big splash because you don't think that's possible. Which, of course, occasionally bites the proverbial hindquarters, especially when the change is enacted without good foundational methodology (hard statistics, preliminary experimentation, etc.) -- which is pretty common simply because of the political cycle being as short as it is. Since groups are in a rush to get things done in a (comparatively) small time frame, sometimes stuff gets left behind in the rush.
Which, yeah, is a problem, but considering a lot of the bigger deal stuff involves studies and whatnot that have been continuing for decades with no sign of stopping, and the problems they're attempting to shed light on are existent now...
... well, the urge to just do something -- try to improve the situation, even in the light of limited information -- gets strong. It gets especially strong when you're regularly involved with the highly... call it shrill? Political situation that seems fairly standard these days. And if/when things do go tits up, it's pretty rare the causal forces are still around and able to exert enough power to make any amends. Bankruptcy or political/institutional marginalization are pretty common in cases where things go wrong, even if the problem wasn't foreseen. People love their scapegoats, etc., etc.