Although I agree with your ideas, I believe an artist such as Picasso is a very poor example. First off, he was a singular genius, which few or any of us will ever be. Second, he was well rewarded for his work in both honors and cash. He had incredible incentive to continue his in his craft.
A possible better example would be Van Gogh, who continue to paint, what are today considered to be master pieces, while receiving next to zero pay or acclaim.
But I understand. Such would punch a grievous hole in the concept that will power is THE path to success.
But, alas, success (measured in wealth and/or public acclaim) is a sum of three components: One, talent. Two, hard work (and yes, this includes will power). And Three, luck.
The third of these is clearly the difference between Picasso and Van Gogh.
Picasso was lucky in that his work was fashionable during his lifetime.