A lot of Maxim's offerings, at least, are startups that they acquired. That seems to be a large chunk of their business model, acquire rather than put in all the R&D themselves.

The specific chips I know of have ARM cores in them.

I wouldn't call Maxim a startup, nor would I guess that their market reach approaches anything like the 95% figure above.

Maxim acquires startups, not is a startup themselves. A good chunk of their products are one offs from firms that won the startup lottery.