E.g. if a business can force everyone to work through their half-hour lunch without pay, they're getting an extra 130 hours per employee per year for free. If it takes them a week (40 hours) to train a new employee, they can have 300% turnover for that role (replacing the worker in that role 3 times) and still net 10 free hours per year.
At 2 weeks of training, they net 50 free hours at 100% turnover and break even at 150% turnover.
At 3 week of training, they net 10 hours on 100% turnover, and would be better off letting people have lunch if turnover is higher than 100%.
Skipping lunch is a weird way to measure it, but it's hard to generalize "how much more productivity do companies get if they micromanage employees like Amazon does" or something like that.
On the other hand, it discourages any attempts to fix miserable jobs. Workers won't bother to try unionizing or petitioning management because they can just quit and management can hire people who quit other jobs. If I'm measuring who "wins" there, I think the company does on the net. They get to keep their crappy, overworked jobs and workers take on the risk of finding new employment. Until very recently, finding replacement workers wasn't really a struggle for management.
I don't think quiet quitting is bad in and of itself, but I think it's symptomatic of underlying flaws in the current work atmosphere. Workers should be adequately incentivized to either do well in their jobs or find a new job, but we seem to be in a period where neither doing your best nor switching jobs has enough incentives to be worth it. That failing is indicative of some systematic failures.