Oh, look, that new movie I'm interested in is coming out soon. Let me weigh my options: I could either pay $10 to, you know, see it, or pay $15 to be distracted for the first ten minutes of it after which I forget about the 3D altogether outside of maybe an action scene or two which I then can't concentrate on because the 3D is damaging my immersion again.
Wait, what's that? The movie's twenty years old, and going to see it in 3D not only sends the message to the movie industry that I want them to keep emphasizing their precious visual toys over any originality or artistic substance, but is in itself stupidly impractical when I could get an improved experience by outright buying it for about the same price or watching it for free on Netflix?
No. Just no. Given that no new release has ever been improved by 3D, the same goes triple for old ones.