> would think the figure of public companies gone bankrupt to be much much higher over that long of a time frame

Bankruptcy is a symptom of leverage. Companies more and more fail by being acquired into oblivion. (It's also common for a dying industry to consolidate until its last gasp.)

There are other exits besides bankruptcy, I think a lot of companies kind of whimper into near bankruptcy and then sell to others or just cease operation without bankruptcy, would need to get actual data, but that is my speculation.

Acquisitions mask a lot of it.

Its why almost no YC companies have “gone bankrupt,” someone one will usually pay a nominal amount “for a team” and founders are happy for the soft landing.