I remember once I was interviewing for a senior position where the ask was something like "design a general purpose system for a REST layer on top of an ORM."
I had just finished implementing an OSS solution that did exactly that, including some upstream changes we made to improve the system, so I walked through exactly what we did, challenges we faced, etc.
I walked out of the interview feeling as though the interviewers and I didn't speak the same language; they might've said the same. Not only did I not get the job, I never got another communication from the company.
To me, senior level interviewing, especially at smaller companies, is fraught. A full 1/3rd of the companies I've interviewed at would not have been a good "culture fit," and I'm a picky interviewer. I expect, like coding tests etc, these interviews are not aligned with the real travails of the position - growing talent, managing time, triaging, and ensuring stability/capability.
I don't believe this is the case for most OSS. Many of these companies (e.g. Sun) had the greatest intentions, however at some point the purpose of a company is to make money.
Some (like Automattic) are lucky enough to do this through hosting and/or a marketplace, but for most it will be some form of open/closed model or lock-in.
Whenever I see a company whose product is OSS take on investor money, to me that is a red flag for the longevity of that OSS software.
Expensive and quality speakers that are basically bricks at this point.