He was great because he brainwashed people with a very effective strategy.
First he never learned to paint academically, instead he faked the signature on some of his father`s paintings (wich were academically acceptable) & passed them as his own.
Also lots of connections & the help of some rich people. (Like it is today).
He DID saw the world diferent, but never acquired the technique & virtuosity to transfer his visions on the canvas & also there was a generally anger from new vanguard artists towards anything academic & add to it the first & second world wars (Hitler & Stalin loved academic art & bashed abstract calling it "degenerate art").
Now art is about brainwashing others about why it is art, the true star in contemporary art is the critic who has an incredible imagination to see things where there is really nothing, no art material with true density.
& people end up believing to this mafia to not pass as idiots.
Never asked yourself WHY is there practically not Leonardo da Vinci followers in technique today?
(and i mean, his technique CAN be used for abstract & non figurative work!)
But lots of abstract expressionists?
The answer is obvious : Making abstract expressionism can be done by an ape, but a work of such care as the mona lisa is close to impossible.
(There is a case where an art critic got fooled with a monkey painting!)
Mondrian, Kandinsky, Klee, Rothko, Malevich, Warhol, etc (late works on all of them)
are NOT art, they are design, groundbreaking if you want, but definetively not art.
A carpet has a nice design on it, but is not art.
Sorry for the bad redaction in english.