For women, online dating just doesn't make sense. Even on Tinder, where the ratio is kinda okay, women are bombarded with messages and likes. To the point that they can't even respond to everyone even if they wanted to.
This means men are left with unresponsive women and just start to send cheaper pick up lines to more women faster. Thus continuing the cycle of women getting bombarded...
There was a blog post I read once where some employee used statistics from the dating site to show what the relationship between male and female profiles where, who had good chance of getting dates etc... Conclusion: it really doesn't work for 90% of men.