You’re not wrong about a lot of what you say, but you are wrong in that RDF tools didn’t ruin community.
I tanked in OG through BC and ran dungeons as dual spec fury prot in LK. Even then finding groups, much less GOOD groups, was difficult. When you found good people you wanted to stick with them and run multiple dungeons back to back. You added them to your friends list and I made many IRL friends that way.
With the LFD or RDF or whatever it completely ruined that dynamic. I would always tell people, “do NOT leave group after we finish. We’ll queue for another.” Even after people agreed and were even seemingly excited at the prospect and we had a fast, clean run with no deaths, someone would leave group to queue again just out of habit or something, then the group would fall apart. Like 9/10 times.
Tge problem with LFD/RDF is there is no investment to forming a group, so people have no incentive to try and create something that lasts.
It also makes the dynamic toxic because people will leave if a tank or healer lets them die even once, much less if you get a wipe. This becomes even more prevalent later into the game when you’re gearing up alts or for people who start late. If you’re an undergeared tank and dps is used to end game geared tanks that let them just zug before the pull even gets in position and the tank in blues is struggling to hold agro they just drop group without saying a word.
You also get more people who can’t be bothered to even type in chat because these random strangers that took no effort to find aren’t worth talking to.
What’s more, instantly teleporting to dungeons then right back to your original location makes overland travel pointless.
It just detracts from the overall experience and makes it feel like much less of an MMORPG and more like an action RPG, which is the problem with retail.
RDF mechanics, 25 daily quests, no attunements, face roll endgame content, and multiple tiers of the same content all introduced in LK were the beginning of the end of WoW.
Edit: Oh, and 15 different currencies with new ones coming out every major patch