A couple of honest questions, that over and over I see nobody take into account.

S&P500's composition changes dramatically over time, and it is designed to do so. Any historical CAPE analysis isn't very relevant if the top 30% of the index is now something completely different vs the 80s and earlier?

Also, shouldn't we start looking at a global index rather than just the S&P500? Many problems go away when include the rest of the world.