Advertising is one of the important elements. But the community, of course, should help developers to promote the project in which it is interested.
I have seen dozens of quite perspective projects that unfortunately just disappeared because unproductive advertising ..
In addition to advertising, all developers and admins should work competently. As the saying goes, "fish rots from the head" If there is no coordinated work, then everything will be gone. It is also very important that the admin composition be not scammers. I do not blame anyone, just saying that the team must take responsibility.