Hopefully your experience is more common. But if this person's is, then the "dystopia" isn't that fictional.
I already mentioned it'd be stupid to put that level of sacrifice into a company unless you were adequately compensated or given enough power/time to accomplish actual culture change. And of course there are modern bigcos who are borderline dystopian where it's impossible or SMBs with sociopath leadership who doesn't want change. Which is when you leave if you can't tolerate the environment, assuming you can, but attempting to change it is a whole different beast.
It's not that managers don't care about their employees, they just don't care if or why you left because those circumstances are outside their control. HR collects that info in exit interviews, and a line manager has no influence with HR. If turnover starts hurting the company's bottom line, they'll do something about it. Otherwise it's not going to be a priority at the levels it needs to (how effective is your "Diversity Officer" in creating real diversity?)
I hesitate to say they "care" because I think that gives the wrong impression. Everybody wants to make a little more money, get a little more freedom in deciding their priorities, get a little more flexibility in their hours, etc. So if you say your only reason you're leaving is that you want more money, they're probably not going to give everyone a 10% raise next quarter. But if you have well thought out grievances that can be addressed without spending millions of dollars or completely changing the structure of the company, I think you'd be surprised how willing executives would be to try and make things better.
This extreme view of business is popular in dystopian fiction and with the pure customer service level interaction with some of the worst mega corps like telecoms companies but I don't think it reflects reality of most people's office workplaces.