I fully expect us as a society to hit the various walls at speed, and have to find some way to do something useful with the various pieces remaining.
But, given that, "working out the useful things one can do beforehand" is useful - because you can afford to screw up, to learn what works well locally, and have the resources to experiment. I'll point to things like "direct solar heating of homes" (solar thermal air collectors) as the sort of thing that take some learning how to build and use effectively, and it's useful to work that out while Home Depot still is tolerably well stocked. And/or to collect supplies ahead of time.
I'm aware it's a pessimistic view, but it's been working just fine for modeling reality.
edit: no techno optimism here... poking around for people's ideas on regular folks relations to state and capital on this issue
Something like "Go Team Star Trek! Humans through the universe!" regardless of the chances of it actually happening?
I think the chances of doing much useful in terms of "long term sustainability and living within our energy budget" went sailing past in the 1980s, so adapting to a lower energy and lower energy reliability future seems wise to me. Though there are certainly useful things that can be done on the path. But I'd be happy with a return to far more local systems of food and energy production, and people adapting to living within the currently available energy at any given point in time. Having "solar days" in the winter like we have snow days is a lot easier than building power systems to deal with a week of heavy inversion at "normal energy use."
Do you see much evidence that suggests otherwise?