a combination of many factors that contribute to the lack of bonafide stars in the previous eras.
1. oversaturation of the fighter stable. way too many fighters, redundant lacklaster fights, forced multiple viewings of fighters that would not even be top 5 in PFL / bellator.
2. UFC's unwillingness to allow fighters to self express in the form of custom fight shorts. their are reasons why tito, chuck, cro cop, other greats stood out. they had a color scheme, personality. they all weren't wearing the same variation of blue, red, green, yellow fight shorts. the UFC does not want to make stars, they don't want to give leverage to fighters anymore.
3. lack of genuine authenticity. few fighters seem genuine/authentic in their response. the social media age, modern pressures have given fighters a lack of uniqueness, all answers similar, all sharing the approved message and sentiments, empty platitudes. when a fighter does speak up, the population doesn't know how to react, besides label it as wrong think. perhaps society's own interpretation and unwillingness to peacefully disagree.