Terradave - where did I make any point about quality? That one era was better than another. Your notions of judgement are your own, not mine.
As far as Rennaissance artists working in large workshops, collaborating together, it was always my understanding that the term "Renaissance man" referred to someone who could do everything himself. Who did Da Vinci work with to paint the Mona Lisa? I was unaware that Michaelangelo collaborated with other artists to create the statue of David.
I'll admit my art history is somewhat fuzzy, but, it was my understanding that art in the Renaissance was generally through patronage where a single artist would be commissioned for a work. I was completely unaware that teams of artists would work together.
It was usual for painters and other artist to have apprentices, just like any other craftsman. And just like any other craftsmen, artists would use their apprentices to do the boring work involved in creating art (prepping canvases, painting solid fields of color, sculpting rough shapes out of marble, etc.) Much of the work in a lot of Renaissance art is actually the work of apprentices. That was how they learned their craft. The master would finish the work of course.