Samalot,
While electrics are becoming more popular these days, they are far from being dominant in the hobby. The popularity of electrics does continue to increase as newer and more powerful motors and batteries are introduced the market, but I feel that glow/gas will be the most used power source for a long time to come. But for many using electrics is more than a personal choice, in some cases I know that electrics have saved flying fields because they are so quite. But I do doubt that they will ever become "dominant". Well, at least in my lifetime (I'm only 41).

Ken