No, it's duping... Sure - players need less and less, but there's much less players than two weeks ago playing... And the dupers are still selling in mass. So nothing really changed. I think they just took a break from duping while the bans were going.
D4 seasons get boring fast. There's really no endgame, no challenge.
2 weeks ago? I mean i quitted 2nd week of season lol. Game is as casual as it ever could be. Duped mats are always sold in bulk anyway. Like i said people either already quitted or had already reached a certain point that they don’t need to do boss runs anymore but rather go undercity for gears. Idk what kind of challenge you expect but diablo is no elden ring or soul like game. Any difficulties added into boss fight or gameplay will piss off the casuals. Since d2, i took the levelling and gearing part as a challenge but d4. They boost levelling to a few hours to max level. Gearing is limited due to no item diversity and great affixes already cancelled out the randomness of loot.
D4 is now a 1-2 weeks kind of game man.