What you want to know is the probability of a small, independent, high quality provider remaining independent, high quality and not bankrupt.

It does seem to be rare in the tech space, especially in the US. Becoming one of the largest public corporations on earth is one way to do it, as you suggested, but the odds of that happening are miniscule.

Except Valve I guess, but that was never a public company that could be acquired to satisfy investors in the first place.