One big problem is that such claims are often cover for what amounts to theft. PE companies loading acquisitions with debt, for example, or "enshittification" - both tactics which are optimized to transfer wealth to investors, not improve the overall allocation of capital.

The idea that all these shenanigans are "efficient allocation of capital" is just propaganda, left over from decades ago before the system became what it is today.

This is where you need government intervention and controls, but unfortunately the US government is structurally and systemically unable to provide that. Regulatory capture, legalized corruption ("campaign finance", "lobbying"), money as speech, corporations as people - none of this is morally sound, and the justification that it's all in service of "productivity gains, lower costs" etc. is hollow.

> but deciding where to draw that line in practice is messy.

Of course - that's the nature of morality, it's inherently political. There would be no morality without other people. But that doesn't mean we should throw up our hands and give up on it.