PE are basically black hat engineers that exploit unpatched vulnerabilities in our societal systems. You shouldn't be any up buy up all the competition in an area but nothing stops you. You shouldn't be able to buy a company, lever it, loot it, and leave it to die but again nothing stops you.
Even if legislation happens, which it won't, it's far too slow to stop them.
This is what happens when someone has total control over an organization, they use it for purely their own benefit. This is why I would prefer more diffuse power structures for organizations in general.
Even if legislation happens, which it won't, it's far too slow to stop them.