I grew up in the 90s, and I don't remember a time when old school toxic masculinity was considered particularly cool on a cultural level. All the media I watched growing up showed entitled jocks as toxic scumbag stereotypes; all violent and rapey and the obvious bad guys. I can't imagine being one of those violent, rapey guys, because I've been shown how utterly detestable they are to people of all genders.
Thing is though, that in painting "the jocks" as the jerks - and by omission, the only way a jerk would look and behave like - it created this huge blindspot with nerds, who everyone sorta understood as the polar opposite of the jerk jocks (which also then assumed that they were equally different inside, emotionally).
I think a big component of what later exploded as gamergate was this completely unreflected dynamic, where there was one type of toxic masculinity, and it was the jock/bully/mainstream-dudebro. It allowed the slightly more subversive toxicity among nerds - of "the nice guy" - to really grow and fester, and which (I think) fueled much of the incel-movement as well.
After all, they weren't the jock from tv. They were the nice guys, who always treated girls with respect. But did they ever repay that extraordinary grace? No. Never. They wanted the jocks that they said they hated, because that's what all women are like. Ungrateful.
(I was going to write more standard repressed nerd-shit but it's honestly genuinely bumming me out to even slip into that mindset for just a moment).
Basically, by honing in on just one manifestation of toxicity, we kinda - as a culture, really - assumed there couldn't be any other type of manifestation.
Culture-critique in the 90's was mostly centered around consumerism, so it kinda made sense that it didn't really rear its ugly head until just a few years ago in a "woah, wow, how could we have not seen this?" kind of way when Gamergate exploded, seemingly out of nowhere, and for the most (at least as stated) disproportionate reasons.