I don't see that as "the Gygaxian style" of D&D; if anything, recent versions of the game have downplayed the other elements. I don't know how long it lasted, but there was a period of at least a couple of years when players in the Blackmoor campaign chose to focus on the dungeons.I mean people can't just keep dungeon bashing for 35 years and not get bored, right?
There's also the old view of D&D as "an amusing and diverting pastime, something which can fill a few hours or consume endless days, as the participants desire, but in no case something to be taken too seriously". In that light, there is no more reason to get bored of exploring the dungeons than to get bored of pushing pawns, drawing cards, or looking for a chance to lay down tiles on score-multiplying squares.