and how many are at this very moment in line for a chance to go? how many applicants for astronaut does nasa get every year? how many does chinese space agency?

there have been 600 people in space not because lack of willing candidates that is for sure.

depends massively on the future pricing of mining ore on earth. one can even deduce that needed regulatory restrictions on environmental damaging mining operations is a must have if we want to keep the earth habitable for humans.

unless you think everyone should either live in a cave or reduce the number of people by 90%.