What are some examples of successful open source software business models?
Automattic with WordPress and WooCommerce. Arduino & Raspberry Pi, and possibly RiscV. TrueNAS (formerly FreeNas). Reddit at one point...
At least some of the most successful seem to be those that are open source in name only. OpenAI, Github, etc. They get the goodwill that comes from being perceived as open source but are completely commercial in nature. I don’t know why most people turn a blind eye to such practices.
I guess Mozilla, but the business is almost completely reliant on its search deal with Google
Not the most successful, but the most innovative recently for solo devs: https://squidfunk.github.io/mkdocs-material/insiders/