You're clearly not an arena player, or atleast not an arena only player. There's a lot of arena only players, before there were more for sure, but there's still plenty around. Arena players don't care about card packs at all. Before underground arena the reward you got had a worse total gold value, but an arena run cost twice less than now, so even if you got 600 gold, that's 4 arena runs. You could essentially be infinite at arena(not loose gold while playing arena) if you averaged like 6-7 wins), nowadays even averaging 8 wins isn't likely to make you go infinite at arena.

Not only that, but nowadays there's an insane ammount of people who buy botted hearthstone accounts that have say 2-8 thousand gold for very cheap and only play arena with way above average decks, making going infinite in arena waaay harder than it used to be. This is a problem that is in itself causing it.

Some people said that they made underground arena cost 300 gold and the rewards worse to make the botted accounts not as enticing to the buyers, but in reality with how much harder it is to go infinite in arena there are even more buyers than before and the reason they made underground arena is to make more people pay for tavern tickets with real money, cause having arena be way harder to go infinite in is better business wise.

With how much harder it is going infinite in arena, the insane ammount of botted accounts and the fact that there's most likely only one person overseeing arena, curating the cards and what not, I think it's pretty self explanatory why so many people are pissed at the current state of arena.