1) PE of 30 can go to 15 if prices come down…. or if earnings go up.
2) Yes there are not a lot of great alternative investments.
3) The last 100 years of awesome stock performance probably doesn’t predict the next 100 years. We are unlikely to look like Japan since 1989 as our population is growing, but many things can change.
4) Diversify, buy and hold, don’t overextend with stupid consumer choices, and you’ll be fine!