Pugging as a DPS always sucked. Its not new, its the whole reason that even when i was maining DPS my alts were always Tanks or Healers going back to TBC (War/Monk/Druid/Sham).
Reasons are twofold and while Blizzard attempted a ton of things to alleviate that, going from extra goody bags to adding entire classes in hope that it would help (was a very specific design goal of the Death Knight and why all 3 specs could originally Tank), it never really worked as they always danced around two of the fundamental problems.
One is the Tank to DPS players ratio being completely different between dungeons and raids. In a 20 man raid you have 1 Tank for 7 DPS players, in dungeons you have 1 Tank for every 3 DPS players. Its important because many people do both activities, but if someone decides to main a Tank, his chance of finding a raid spot are slim, while if he plays a (Ranged) DPS, its very easy. Like seriously, go look at Guild recruitment forums/discords, its the complete opposite from the M+ LFG tool. So everyone flocks to DPS classes to raid then once their raiding is done, allof them fight for the same spots within the groups of much less numerous Tanks/Healers. Solution here is pretty simple but does require some fundamental, expansion worthy changes, and that’s to change the dungeon format to 6 players…
Second main issue is that these roles mean being responsible for the rest of the group, while DPSers are only responsible for themselves, its extra pressure that a lot of people would rather not deal with in a game they play to unwind, specially since it also means sometimes dealing with toxicity should things not go perfectly during a run.
Lastly, but it is Blizzard somewhat tried to address, its just not perfect, is the fact neither of these roles feel good to play in the open world or other casual areas of the game or in PvP, so people learning the game won’t gravitate towards them, meaning even less people playing them.
Tl:dr : there’s fundamental reasons why pugging as a DPS sucks, its always been this way and its unlikely it will ever change.