If Company A sucks and there are many other companies that don't, every single employee at Company A could quit and go work somewhere else, and then Company A can go out of business. That's a completely reasonable outcome for a company that sucks, and is what happens when there is actually competition.
> and we certainly can't not-work at all.
No known system satisfies the criterion that we all collectively don't have to work.
> Moreover, if an "employer sucks", it may suck in multiple ways - environmental impact, social impacting where it operates, impact of its products and services on society etc. None of that changes even if you do go "work something else". What's necessary is improving things, not finding another 'stall' in the 'market'.
These are not the "Soviet Shoe Factory" issue, they're externalities. If the company tries to make only baby shoes to save material but people want adult shoes and competition exists then people buy adult shoes from somewhere else and the shoe factory making unnecessary baby shoes goes out of business or doesn't have the perverse incentive to do that to begin with.
If the company is dumping toxins in the river, that isn't one of the problems that competition is expected to fix, in the same way that it isn't expected to prevent thefts or murders. And it's also not a problem the Soviets fixed either.