Can put new acrylic over old 2pac as long as it's prepped properly.

But you're right, you can't put acrylic clear over a new 2pac base.. can't put any acrylic over new 2pac or else it will flare (get wrinkles).

Are there any painters who still use acrylic?

I only know of it being used on show cars as it's easier to cut, buff and polish.