I kind of doubt this is true about “most” players. I don’t believe there’s any way to prove it without access to Blizzard’s data. Anecdotally I know I did far and away more dungeons after Dungeon Finder came into existence. I might have been “done” with them on my rogue main, but then I had a paladin, druid, death knight, and warrior. All told I completed at least 10 times as many dungeons after RDF than before.
During these conversations here I’ve seen that not only was I not some weird outlier, we were maybe a slight minority. Potentially even in the majority.
I agree with both of those observations.
And you’ve completely lost me. I had a lot of fun in random dungeons. Sometimes we were rambunctiously chatty, others less so. I specifically remember several dungeons where nobody said hardly anything, we knew the dungeon backwards and forwards, knew our roles and executed them, completed in record time with no deaths, and at the end someone said “That was awesome!” “Yeah, wanna go again?”