Why are anime protagonists of the 80' and early 90's (Ken, Goku, Jojo, Ranma) so cool and the ones of today just don't measure up?
It's the same trend with Hollywood. In the 80s and 90s, you had Schwarzenegger, Stallone, etc. Nowadays, action stars like them aren't popular.
Otaku stopped just being fans of the industry and started working in the industry. And as such, they bring their own personal emotional baggage with them.
Devilman and Black Jack shits on them.
Interesting you should mention Jojo.