There's obvious sampling bias here. The companies in CrunchBase are not chosen according to objective criteria. They're chosen because someone visited the CrunchBase website and added them.

It's not a big surprise that the only semiconductor companies anyone bothers to add tend to be the successful ones.

And, your company can be a cash cow even if it never gets acquired or has an IPO. I suspect this applies to a lot of consulting companies, but what would I know?