> Beyond some size (some revenue, and/or more than 500 shareholders), even a private company essentially needs to make all the disclosures that a public company does;...

I don't think that's true. Do you have some source that confirms this?

If you go e.g. to Cargill's website (a $100 billion private company), you won't find any detailed financial information. There are some high level numbers and their yearly report is some marketing fluff. Same thing for e.g. Ikea.

As a public company there is relentless pressure to deliver ever increasing quarterly profits above anything else. Trying to focus on anything else (e.g. sustainability or long term plans), opens you up to criticism and lawsuits from your stock holders.