Yea - the thing that a lot of comments seem to be missing here is that evolutionary pressure comes in the form of mass die offs of those unfit for the new envir

Yea - the thing that a lot of comments seem to be missing here is that evolutionary pressure comes in the form of mass die offs of those unfit for the new environment. If some people just have a higher incidence of cancer when they're 40+ there will be essentially no evolutionary pressure unless it's socially enforced (aka eugenics which is a really bad idea).