I don't know anyone (at all) playing
4e, so for me it's like 3rd edition has just stopped printing new books. I'm not really interested in pathfinder. I
finally have a complete set of D&D with the guarantee that no more books will come out.
So I'll continue to run my games in 3.5 and if new players come along who don't know 3.5 then I'll teach them.
Maybe 5e will interest me. I'll get back to you on that one in 10 years.
Besides, if it ever reached the point that I could no longer find people to play 3rd edition, I'd just run GURPS instead.
4e is irrelevant to me.