There's $32trn of them: https://fred.stlouisfed.org/series/BOGZ1FL594090005Q

Who do you think is buying .. everything? They're holding substantial fractions of both the whole stockmarket and national debt.

I do not know anyone other than teachers, cops, or firemen that have pensions and all of those are grossly underfunded (see city of Chicago).

Now... if you mean IRAs then yeah... that's 99% of all private "investors"

EDIT: I forgot all about State and Federal pensions.