[kcovia]

It may have been smaller, no doubt, but this statement is not correct:

But in the 1400s, just being an artist is a huge enough accomplishment that people are going to know who you are.

Artists in da Vinci's day were more akin to craftsmen. Da Vinci himself was basically raised in an artist's workshop (by Andrea del Verrocchio) and worked alongside dozens of other students on their master's projects. This is in stark contrast to today's artists, who are basically expected to be the sole creative genius (barring people like Damien Hirst, of course, who is known to use assistants.)