Artsists started to become "stars" because their work was recognizable and expressive of current philosophies and values. They had their own styles and they were highly skilled masters that took visual art to new levels.
We absolutely have artistic masters today. Many of them are coming from atelier schools which are making a come back as we are seeing somewhat of a renaissance in realism occuring right now. I draw a distinction between star and master. That is to say a master isn't necessarily elevated to star status, nor are all "stars"necessarily masters. I use the word "genius" very carefully. I use the word "master" very carefully as well. It's a title one earns through mastery of a skill or great knowledge (usually both). It's not deserved just because your best friend's cousin is an art critic for the New York times (for example).
I feel that art has been hijacked by pretentious hacks who relish the smell of their own farts just a little too much. Crtitics and pretentious snooty art "schools" have taken over and have attempted (and succeeded to a large degree) to render the word "art" completely meaningless. I hear it all the time -- "anything can be art". Well when anything is art, nothing is art. And that's why much of modern art academics is focused as heavily, if not more heavily, on justifying crap as art through rhetoric, as the production of actual art.