I once worked for a unicorn (1B valuation) company where there were there were <35 engineers and all of them reported to the technical founder.

No mangers, no product managers, no appraisal (30% hike or out)

The rule was "I will treat you like an adult and you have to act like one"

Easily the best company I worked for and best Colleuges.

But I have seen this model hiccup once it reached ~70 engineers.

May be because of the structure or may be it's difficult to hire more such engineers India. Might scale better in SF.