It's because the people who took them back then are now old, CEO age and powerful and making decisions. They are not popular in the normal use of the word. But

It's because the people who took them back then are now old, CEO age and powerful and making decisions. They are not popular in the normal use of the word. But "officially accepted" is more accurate. Psychotherapy is popular. (We should expect things which are unpopular now but that the kids are into to be accepted in 40 years time.)