I don’t think the west is necessarily doomed at all. People who say that are usually angry that they no longer have all the power/privlage to themselves and can no longer get away with say, ruining a gay person’s life or forcing black people to remain “the help.” However, if it is doomed, it will be because of income inequality and too much bootlicking of “betters” more than anything.
As for solutions, I think it’s a mix of everything. Numbers, humanity, all of it as many problems are complex ad will require complex solutions to fix the,.