IDK, I feel like with things GlassDoor and Indeed that might be changing. Granted, reviews in those places are anonymous but companies will definitely loot at their culture and management if it starts to impact their image.
Sure. The important word here is anonymous. If there is a systemic problem at a company and the GlassDoor ratings consistently say that the same thing is wrong, a company will try to fix it.
Also note that companies perform exit interviews. If they consistently hear from departing employees that X is an issue, they will fix X because having a high turnover rate is expensive. Every company cares about turnover rate.
I can say that the company I'm currently working for doesn't, they only care when it affects their bottom line. They're more than willing to put people through a perpetual crunch rather than to hire the number of persons necessary in order to properly manage the workload. It has affected different departments and led to many firings and quitting from people that were burn out. It was only when they actually saw the magnitude of the mess they made that they began to amend things a little, and now it seems like they might be going back to what it was before.
TL;DR: exit interviews mean squat when the problem is the boss.
Same company as mine? xD