I think the difference today is that the normal path is that an artist does a lot of stuff, potentially quite innovative, and is _then_ discovered (or not; see Van Gogh for instance). And at that point, maybe discovered by the market, not a single patron; I believe an artist having a single patron has been rather unusual for at least the last century.

A few hundred years ago, by contrast, artists tended to get into it via, essentially, apprenticeship to another artist, and attempt to get a patron that way. Some artists ended up being technically proficient, but stylistic innovation was very, very slow and minor by comparison to the late 19th century on.