If you think they can save us, you are.
I have no idea if we're facing the end of the world. However the big picture that most green activists, including the Transition folks and most permaculturists I've met, fail to take on board includes some very simple, stark facts. The entire planetary biosphere is collapsing, including the oceans, rivers, lakes and land; we are going to break the 2C degree safe threshold (which wasn't safe to begin with) within a couple of decades even with our best efforts (which we're not giving); we will break 4C and possibly 6C with BAU; the agricultural systems of the world are destabilizing before our eyes due to extreme weather; methane feedbacks may have already begun; the world's populations of human beings and their food animals are exploding while the world's population of wild creatures is imploding; the bees and bats are dying; starfish are melting; sea turtles are dying on the beaches. It looks a whole lot like the global life-support system is coming apart at the seams, and we are doing what we've done since this became a recognized problem 50 years ago: precisely nothing.
This is not a situation that Transition Initiatives or permaculture or appropriate tech can ameliorate, because it looks to me like we're headed for world-wide economic breakdown, social breakdown, dieoff and eventually human extinction. How eventually is still an estimate, but a good bet is sooner than later.
This is what I mean by inevitable, no exit. Not boom we all fall down. Not with a bang, but with a series of low, pitiful, drawn out whimpers from every living/dying organism on the planet. Anyone who can say, in the face of this evidence, that we all have a moral responsibility to "work tirelessly to make things better" or that this or that approach will "save us" is the victim of a blindness so deep that it can only come right up from our DNA.
Now, those who DO get it, and prefer to do these sorts of things because it's what humans do and we should all leave a small space for a miracle in our Flowcharts of Doom, well they have my complete empathy. So do those who simply say, "You know, I think I'll just take a walk and look at the sky." But the moment the word "sustainability" crosses someone's lips, it's like they lit up a a big neon sign that says, "I'm blind. Please follow me!"