Maybe you already don't find cows beautiful and so didn't appreciate the metaphor. Here's another take: Driving the road to Hana on Maui, I think you drive by like 50 waterfalls. We were in awe for the first dozen, but by the 50th, it was just another waterfall. Or seeing nonstop bald eagles in Alaska, by the time you leave, they're like pigeons.

The point being made exactly that something beautiful has being cheapened.