If that's the lesson you learn from reading about why women don't report, and after several of these debates, not much I can say. Seems you're determined to blame victims for not willingly exposing themselves to being victims AGAIN and ruining their careers and/or lives for no gain. Women aren't the problem here.
Why don't people getting shaken down by the mob go immediately to the police? Gosh, maybe the prospect of getting burned out, beaten or killed is a deterrent, plus if there is a history of the mob not facing consequences because the accusations are very hard to prove and the mob hires good lawyers, that might be a factor too. Seems obvious, right? They also got what they wanted out of their relationship with the mob - an intact business and to continue living with their limbs and teeth intact! Now apply that same principle to women sexually assaulted or harassed and you have your answer.
As to what set them off, that seems completely obvious, too. One replaceable actress against Weinstein is incredibly tilted in favor of Weinstein. If it goes public, it's her word against one of the most powerful men in Hollywood. Why would one woman with little power make false accusations against a rich person? Money of course. Or she is a whore, and now wants to be paid, or sees nothing to lose, whatever smear his $500 an hour lawyers come up with. But do that, malign her, and he's won the PR and likely legal battle. IF it's 10 women, all with similar stories, over a period of years, that power imbalance changes, quite a bit. Why would 10 women, not otherwise connected, all tell similar stories of abuse against an INNOCENT man?