The thing about him is that he basically became a millionaire at, what, 25? If he had kept working regularly he might've become a more interesting artist instead of stagnating at whatever age he was when he hit it big. I just think for all his failures as an artist, the way he's perceived in contemporary comics culture is totally disproportionate to those failures.
I think your point about laughing at old middle school photos is spot-on -- Liefeld functions as an avatar of everything people who read cape comics today don't want to be associated with and I think a lot of how people think of him today comes from that. Like "Oh, we're not like that anymore so please take us seriously!"