My personal experience: women do speak out for years, either to silence or to active oppression.
Every single time a man is outed en masse as a predator, there's years and years of women complaining and speaking out about him: tweeting about him, posting online, making complaints to Equity, making complaints to producers or to their agents, sharing warning stories with other women in the industry.
All this simply never gains any traction until one day it either reaches a critical mass point, or a specific trigger happens.
The trigger could be different things: harassed the wrong person (didn't realise that female extra was the niece of a journalist or a producer); former victim finally reached a level of power in their own career where they could take action; had a project flop so no longer protected; pissed off the wrong people; journalist interested in MeToo happened to meet a former victim.
Was it the Guardian that connected these incidents? Or women gradually talking to each other?
Yeah it could be both/either these things.
I have a personal (second hand) connection to both Weinstein and Spacey, and in both those cases everyone knew, but those men were protected because they were so powerful and their projects made money. In Weinstein's case, a lot of people basically waited for years ready to pounce the second his career weakened (meaning the second his films stopped making money). In Weinstein's case other Hollywood power players with an ulterior motive in bringing him down leaked certain info and guided journalists and sources together. In Spacey's case, Anthony Rapp was powerful enough to open Pandora's Box (I don't know why he decided to do so when he did) and then that allowed everyone else to chip in.
I don't know how it happened with Noel. Why now specifically. Obviously the Bafta award was a trigger.
But yeah. Women have been complaining and speaking out for years.
Three years ago I made an official complaint to Equity over being sexually harassed and sort of groped by a TV actor. They completely ignored it and tried their hardest to silence me. What happened wasn't 'bad' enough to go to the police and my own behaviour isn't something I'd like put on trial. So I have no other options. But one day he'll be exposed and I'll be there, and everyone will say "but how come froggy and those other women didn't speak up sooner?" WE DID.