Unless I’m misunderstanding your question, the specific server is more important than the software they’re running; it doesn’t matter if the software is being developed long-term if the server shuts down in the short-term… your community will go down with it.
This is the answer. Pretty sure, for example, MetaFilter is running bespoke code for their forum (which means no development at all), and it’s been online since 1999.
Unless I’m misunderstanding your question, the specific server is more important than the software they’re running; it doesn’t matter if the software is being developed long-term if the server shuts down in the short-term… your community will go down with it.
This is the answer. Pretty sure, for example, MetaFilter is running bespoke code for their forum (which means no development at all), and it’s been online since 1999.