RHEL is only free for a limited number of personal or developer licenses.
I don't know the exact limitations, but for a personal home lab that seems fine. For companies, I imagine they could either pay proper for RHEL, use free CentOS Stream or Fedora, or some other server distro like Ubuntu or SUSE. Why is there such a need for RHEL specifically?
Just a guess, but I'd posit that revenues from RHEL support contracts pay the salaries of CentOS Stream and Fedora developers and maintainers.
I could be completely wrong, but given that the latter two feed the former, it would make sense.