You CAN turn off watch history in Youtube (not sure about Spotify). However, for better or worse revealed preferences seem to show that people prefer automatic content recommendations over doing the search & bookmark work themselves.
If companies actually think "users really, really want X" then they should have no fear making X opt-in.
But there are obviously MANY things we prefer to keep opt-in. E.g. sharing my recents data with 3rd party advertises. No need to throw the baby out with the bath water and make every service awful by default just to have a universal rule to quote though.