The customers (multinational and middle size companies, ranging from telecoms, banks, governments, goods and services) pay for support and features of the software. Software has always bugs and CVEs that need fixing, or new features, or needs for securing its supply chain (with SLSA, SBOMs, etc).
There’s a handful multibillionarie companies that follow this approach with open source: Red Hat, SUSE, Canonical, VMware, etc. Particularly in cloud-native tech like Kubernetes and all that gets deployed on top of it.
If a technology is not open source it really doesn’t exist anymore. Customers have learned from the last 30 years and run away from vendor lock-in (AWS, AKS, Google cloud services…).
Mmh, and if I go by your nickname, you are Jason Kaye, influential hardcore DJ and dead since a year.