I would say if you averaged out nerfs over the last 6 expansions it’s more like nerfs every 6 weeks / 2 months (ive not done the math so might be wrong.)
I’d say the problem is more why aren’t blizzard spotting problematic cards before they’re even printed. Are you telling me no one saw Crabrider with 4 hp at 2 mana being a problem at any point? Or none of their testers were big brain enough to work out lunacy could get you all the best spells from other classes on turn 2?
From bronze 10 to legend all you see is the most efficient T1 decks so even after nerfs it’s of no consequence really, and as blizzard don’t seem to be able get a balance where more than 3 decks are playable you’ll just be queueing into the same decks within a week of nerfs landing