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.

Man its amazing when you have that high trust environment. You get treated like an equal, your opinion gets respected, and you can really make a difference in the company's prospect. Its addictive

It's a coordination problem. 70 amazingly responsible adults still need to coordinate amongst one another. Ad hoc coordination and communication always breaks down eventually.