I think you may be missing a key point here. These communities spring up, at least in part, because a group of people all want X to exist and building X alone isn't really feasible. This necessity of collaboration can be a major driver of community-building, especially for people who are very technically competent but not particularly outgoing.
If an AI-generated version of X already exists, at least some of the people who might have joined the "let's build X together" community aren't going to sign up anymore. Some of them may feel discouraged because AI got there first, while some may simply feel like the AI version is good enough for their purposes.
You may be right that new and different communities will spring up around AI-generated projects. I'd argue something is still lost, even if something new is gained in the process. I think there's something special about communities of people who are passionate enough to do truly hard things that require dedicating large amounts of time and effort. While AI can help people accomplish far more than they otherwise would've, reducing the amount of human effort and attention that goes into any given task is almost inherent in any AI use.
If an AI-generated version of X already exists, at least some of the people who might have joined the "let's build X together" community aren't going to sign up anymore. Some of them may feel discouraged because AI got there first, while some may simply feel like the AI version is good enough for their purposes.
You may be right that new and different communities will spring up around AI-generated projects. I'd argue something is still lost, even if something new is gained in the process. I think there's something special about communities of people who are passionate enough to do truly hard things that require dedicating large amounts of time and effort. While AI can help people accomplish far more than they otherwise would've, reducing the amount of human effort and attention that goes into any given task is almost inherent in any AI use.