That's exactly Taylor's point. DaVinci had no such concerns. Atheism was not culturally accepted. There was no Christopher Hitchens lecturing at the downtown Rome YMCA.
Aspirations haven't change, but the ultimate objects onto which we project our aspirations have changed. Of course there are historical particularities, but the objects of transcendence changed over time- from a Biblical God, to nature/science, to the individual. The world at DaVinci's time was theocentric. Now it is anthropocentric. And that is reflected in the difference in how DaVinci painted a chick and how Picasso painted a chick.