When Vince dies. And that's a big maybe because women don't headline in NXT under Triple H, either.
It was all PR. All these first time accomplishments, all culminating in the first ever womens main event at WrestleMania. It was never going to be a sustained thing after that. I called it, when that was done, the womens push was done.
Bayley vs. Sasha headlined a Takeover.
I think Charlotte will definitely headline a PPV again. Ronda too if she ever comes back. Becky will probably main event again too just because Charlotte and Ronda will need opponents and Becky is the most popular woman they have.
I can't see them main eventing WrestleMania again until Triple H and Steph's kids do it.