Sorry Placid but I'm inclined to disagree. I wasn't saying turn based combat has been REPLACED by run-n-gun games, that combat will most likely stay real-time.
There's a reason that ipods get larger and easier to use. A reason we look for more fuel-efficient cars, faster computers at a reasonable price, ect ect ect.
Turn based combat, player 1 attacks, player 2 attacks, enemy 1 heals, enemy 2 attacks, rinse wash repeat. This method, was used until about, the N64/PS age . . . ever since then, most of the gaming industry has realized there are more effective, fun, interesting ways to handle combat. Admittably There have been a few games in the past that have tried venturing into the past by using turn based combat, but these games were majorly unsuccessful, there's a reason, they're trying to use some classic methods, in a boring way.
Like I said, if a game uses turn based combat, it had better be creative, cause it won't sell most gamers.