Well, Diocletian's master plan didn't work, and the Roman Empire fell anyway. But it did produce a medieval mind-set that saw stability in knowing your own place. It was a deal that was hardly inspiring to the upwardly mobile. Yet when dealt with lemons you might as well make lemonade, and perchance in every few generations would be someone in the lemonade guild who could stir the supreme refreshment.
And so it was with not only cobbling shoes but cobbling music as well, as in olden times the arts were less a diversion than a trade. And as with any avocation, every so often you would produce a master cobbler. It does get you thinking about the natural frequency of genius in small populations of folks who are straight jacketed for generations into career tracks and the invariable one track mind.
That's the Bach family for you. For over two hundred years music was their craft, and music was handed down from generation to generation not like an heirloom, but like a craft that needed to be mastered in order to pay the bills. And genius came naturally, and as with every odd generation of craftspeople, sometimes the genius was supreme. But it was all blue collar stuff, no Juilliard training here. Just complete an apprenticeship like a junior plumber, and writing fugues become as natural as installing storm drains.