I've no doubt those interested in the hobby will continue to play and create content, that wont change. But will the grognards be switching over to the new edition? We already know (and have been promised) that it will mutable enough to emulate almost any edition available, and with dndclassics.com going about releasing all the oldschool modules will people still stick with their S&W, C&C, DCC and others?
I know for a fact i'll be picking up at least the core books - our group really enjoyed the playtest, we just wanted something more polished. Who knows we might jump ship. I can tell you we'll be taking some things with us, Backgrounds, One unique things and Icons if we do.
Let me know, what system are you and your group with at the moment and where do you see yourself at the end of year?