Find local public spaces and plant seeds, any seeds, just do it.
But too much focus has always been on single cause theories when talking about collapse. Mumford put it best: "civilizations don't die of old age, but the symptoms of old age." You're right that running out of oil doesn't mean the end of civilization, but you have to understand the nature of this global civilization, which is absolutely impossible to run without cheap energy. As oil gets continually more expensive and harder to get, it's just like pulling the thread on a sweater: it gets tighter everywhere else.
So what happens is that you get further unrest in the periphery, where you'll see more places like Iraq where vast portions of the worlds' oil supply are being torched by insurgents. You'll see more war in these areas over access to that oil, but also (in the case of the middle east) over water rights and shipping networks. Having oil means nothing without people to run that machinery.
And you'll get the same thing with agriculture which is completely dependent on oil run production, esp. in terms of being redistributed. But as the climate heats, droughts, run off and other less forseeable events all come into play. And global distribution brings up further problems like a potentially global disease pandemic unlike anything that the world has seen before along with potential crop extinctions (like almost happened to the bananna a few years ago).
This is too large and too spread out to absorb the loss of cheap energy, and there are no alternatives either. There was a chance 30 years ago when all the ecologists started saying 'oh shit', we've got 50 years to switch off this. Well it's 30 years later, we've done nothing, but expect we can recover in the meantime even while little change is being made. And while those ecologists predicted a huge population increase, they couldn't have forseen that China would emerge as such a powerful consumer nation that could increase almost 5 fold a year in their demand for oil.
So it all comes together, and like every civilization in the past, we are collapsing. I wouldn't put faith in history. Without advances in technology AND new places to go, this civilization would have collapsed long before us. But now there is no place new to go and with oil alternatives still requiring oil and only being able to take 30% of the current oil demand (which doesn't even account for the fact that ones like biodiesel are capable of producing any fuel in the long term if the bulk of the world is turned into rows of corn strictly for fuel), I don't see how anyone thinks this civilization can survive what is coming and what is happening already.
And I know this must happen, and I want it to happen, but I don't want to pretend it will be anything less than chaos in the worst sense of the word for sometime until things stabalize again. (I'd say a minimum of 100 years). SO the more people do now to diversify their actions, meaning rewilding and resisting, but not being afraid of some people doing more of one or the other so long as they understand their tied relationships, the better off things can be.
Permaculture, Permaculture, Permaculture, do it now, learn, build.