The community isn't the forum... it's the people who inhabit it.Is it really helpful to say "this community is no longer entertaining me?" If this community has been of value to people in the past, they might try driving a revival effort before just giving up. This place is whatever the people here make of it. Not seeing interesting thread topics? Try posting some!
people new to the site are invariably looking for help or assistance, the established members are generally looking to help people or just to interact with fellow hobbyists.
the forum is competing with other social media for members, and it's easier to interact with friends elsewhere.
And it's clear to see the attitude of a lot of people who need the assistance, which doesn't lend itself to people hanging around here to offer advice.
A lot of things that had historically added value to sticking around, competitions and chat for example, have now gone. the forums advertise a convention from 2013, competitions haven't been run since 2012, who knows when there was last a post of any relevance from the admin.
If people want to share and have activity, it's easier to go somewhere that shows signs of life rather than staying somewhere that looks like a ghost town.