Google Groups has been left to die
Google Groups has survived 22 years. How many self-hosted Discourse forums can say the same? If you're working on a new, small side-project like a new formal evaluator, are you going to want to spend your limited administrative bandwidth onboarding new contributors, responding to feature suggestions, talking to users, etc, or are you going to want to spend it trying to wrangle self-hosted forum administration and figure out email delivery? the article has a one-line tossed off aside at the end to say "Certainly self-hosted FOSS communities can die, but these are functions of community activity itself rather than the service they’re hosted on", but without considering that the absolute most crucial time for community resources to survive is through periods of lackluster or nonexistent community involvement. If you have a Google Group full of, say, formal methods programming experts, then it can spend 5 years fallow and still be chock-full of absolutely vital historical resources and even spring back into life as people start using it again for discussion. That sort of longevity just can't exist if someone stopped paying the hosting bills for their self-hosted TLA discourse forum 3 years in.