Limited output, compared to Demand.
Influence, if relative. If buyers want crap, others will imitate.
Fame is in the buyers (and potential buyers) eyes. Advertising helps. If the Rich say it is what they want then instant fame.
Many People can take beauty for only so long.
Then when something ugly comes along they have to adore it as a Change. You may note the same in Music, through the last century.
Picasso just happened at the right time. After a while the Elitists were stuck with it, and could not let go. So continuing Snobbery has caused it to rise in value. All art has a value to each person in time.
I like paintings that are photographic, but an occasional ugly or distorted work makes for a change and appreciation of the great works.