I think to some degree the writers know this, which is why they ham it up anytime someone other than Michael or George Michael says something sincere (even with stock tear-jerker music at times).
I'm not going to write some master thesis about why the show gets away with basically offering little content, because I think it's clear that alot of people dislike it for the bulk that it leans heavily on and it would be both attacked and framed as an us vs them from the get go. But I will say that what makes this show entertaining, and which is really hard to pick up on with commercial breaks, is that for all the self-aware writting that goes into it, it's an actors show. None of it would work if you had any less of a cast in any set role. Not saying that Portia de Rossi is a great actress or Will Arnett is the most underappreciated actor of our times, but the casting is spot on and the actors make the writters job easy since the characters various archs are so detatched from one another. You gotta at least give it that.