Well we got System of a Down out of it so I'd chalk it up as even (yes i know they aren't the most "mainstream" act of that era)
I'd say most mainstream rock of any era kinda blows. Aerosmith? Def Leppard? The Doors? I got some opinions
Wow I almost forgot SOAD, definitely up there with the examples of total cringe that I listed in the OP.
It's almost like after this era of rock music people just totally gave up trying to produce it in any mainstream sense because I don't think there have been many successful mainstream rock bands since then.
80s - Talking Heads, New Order, Metallica, Sonic Youth, etc. Yes hair metal was kinda cringe but if you quit lying to yourself you have to just admit it was pretty fun at times
70s - The Rolling Stones, Led Zeppelin, Fleetwood Mac, AC/DC with Bon Scott, etc... really the 70s was the peak of mainstream rock n roll imo
60s - Jefferson Airplane, Velvet Underground, Pink Floyd
Before that it's a grey area but I just strongly disagree that mainstream rock has always blowed.