There have been SF stories that propose an escape into space, or Antarctica, or the deep ocean. But I think faith in those routes is weak nowadays.
But what I think might happen is that a viable 'outside' could exist in the same geographical space as the 'inside'. We can see it already in the practice of war. If you want to make war on the powerful industrial nations, you don't do so from an external offensive position, because you would be nuked. You do it by interpenetrating the same geographical space, and by recruiting people from within one world to move into your world.
If people could make a living in a shadow-world which interpenetrates the same geographical space as our culture, then people would move into it as our world becomes insupportable. For example, if there were hospitals in the shadow-world, and schools, and everything, then people could live there - just as America or Australia eventually became livable by families not just by adventurers.
And I think the shadow world could be more viable in the long term than the hierarchical repressive world. For example, if clever people are excluded from Universities for being 'the wrong type of person' - I've said this before - in the end this is a problem for the Universities, and for the hierarchy itself. There will be another world into which people can move, and this world will then have all the cleverest people in it. And our world will have educated only the rich and dumb. Who is going to win then?
A flexible and egalitarian economy would be more efficient and effective, and more fun to live in. People like to be able to exercise their talents and to be creative. People don't like having to obey low-IQ bosses. If they have a choice smart people will move to the flatter looser structures. Perhaps they will start to have that choice.