Ahhh! Ahhh! Ye hath insulted me greatly!
First off:
Gauntlet Legends and Dark Legacy were very different from Gauntlet. They had a lot of similar elements, yes, but the original, where my avatar and name come from, was much less of a "make numbers go up" and much more "fight your way through variety of mazes while collecting treasure". While Legends had leaderboards based on who was the highest level, the original was based on how many points you got per coin. Crazy, crazy awesome, because it meant that it was about finding the routes with the most treasure AND the least enemies who would hit you.
Secondly, while both of the newer versions did suffer a lot from the fact that the more quarters you pumped into the machine, the better you got, they also had distinct advantages over WOW: they were social instruments. You could easily spend a dollar a day for four friends to gather round the machine at lunch time and just have a couple minutes of silly fun. Quick, easy, and not time-consuming or leashed with monthly fees.
Third, there's a definite "end" to each of these newer games. A final boss to beat, a real "ending" to the story, a point where there's no reason for leveling or getting better armor or weapons. That alone makes them a very different class of game than WOW. They have a point at which you are no longer teased. Sure, there's "extras" to unlock, but those are still limited (Unlike WOW's armor and raids, which are constantly updated to prevent an 'end').
Fourth, if hitting "A" repeatedly is brain-dead and not requiring any skill, therefore not worth doing for story, does that mean that watching anime, which requires even less skill (put in disc, press play) is brain-dead? Watching anime is practically cheating. There's no skill or even work required for the reward. Yeah, the games are brain-dead. It's not always a bad thing.