This comes up so often that I have a stock answer for it:

Well, here we are in the 21st century and some people still ride horses, shoot rifles that you load by pouring gunpowder down the barrel, hunt with bows and arrows, sail wooden boats powered by wind, write with fountain pens, keep old steam trains running, and even fly control line and free flight model airplanes. My bold prediction is that decades from now, people will still be doing all these things in addition to flying "traditional" RC planes built from balsa and powered by glow engines. Why? Because this is a hobby! Because the scent of burning castor oil is perfume to their noses and the sound is music to their ears. Because they simply love glow engines! And I say, more power to them! It's their hobby, let them enjoy it!