Wanna the join the legions of people who have predicted the end of humanity?
Woah, hey, why the false dichotomy between doomsday and 'humanity shall prosper forever'?

There's plenty of evidence showing that things might just get rough in the future, and in fact the future may transform human societies into something scarcely imaginable to ourselves, but on the basis of the unique developments of the past few millennia you feel confident predicting that the existence of humanity itself is a panacea to humanity's problems.

Wishful thinking on your part, I'm afraid. You need more evidence than vague allusions to past problems overcome. Interestingly though, you don't note that the old problems are precisely what the new problems threaten to recapitulate. For all we know, there could be a cyclical fate awaiting us, or even something totally in the Z dimension...