It was definitely more fringe back then, im sure a piece of it is percentage of population using it but certainly other factors. Social media also gave women way more access to men outside of their direct area. Attention became a lot easier to access. T levels probably play a large role as wellOnline dating was around since the mid 1990s, why did it take 10 years to manifest if this was the case? The numbers of men having sex increased for over a decade+.
I'd say it's due to low T levels reaching a tipping point/point of no return and lack of socialization skills due to constantly being on a screens rather than in person with people.