I was at Red Hat very early on. Red Hat has been remarkably consistent throughout its journey once it graduated from selling boxes of software at book stores (which was a necessary step). Red Hat only astook venture money once it was ready to go public and never before. The philosophy of Red Hat was to "make the pie bigger" and still largely is, therefore it supports open source first before anything else. This works because it provides product-market fit at scale and by nature. The thought that "all" Red Hat sells is software support, certifications, and subscriptions to updates is so short sighted and misses the point.

Red Hat created an industry and all of the successful enterprise Linux distros have followed its model to some extent or another (Canonical, SUSE, etc). You don't need "open core" (which is a misnomer if there ever was one) if you continue down a path that creates and maintains communities of software authors out there in the world that will constantly feed value back into the ecosystem.

A virtuous cycle of community maintained software alongside a thriving and growing business is still achievable, no one seems to have the guts to do it.

(edited for typo)