For anyone not familiar with the world of academia, grad students actually have a good bit more power available to them by organising sensibly than you might think. The same is also true for early career postdoctoral research staff. This is because most of the work that actually matters is being done by these individuals, in a very pyramidical structure, but the money stops rolling in without the work that the base o…
Yes, you can push back against advisors who require 12 hrs a day in lab. But if that means you take longer to produce work, your letters might be just good instead of positively glowing, which might mean you fail to launch in academia. Several hundred other people will apply for each tenure track job you apply to; those with "just good" letters tend to get crowded out. The tenured advisor might have a bruised ego because their publication rate has slowed, or be more frazzled because they have to save money and write more proposals, but at least they still have a job.
Also, PIs themselves generally work a lot as well (often the ones insisting on lots of hours from their students think, rightly or wrongly but based on their own experience, that that's the only way to succeed....). I agree academia is broken, but think it's at a deep structural level, and more complicated than schools exploiting students and hanging them out to dry.