So, what else is new?

There's a lot of debate on that point, even among very knowledgeable people. I'm of the school that chain wear happens within the chain itself, so sprocket condition has little, if any, effect. In my belief system, chains wear sprockets, but sprockets don't wear chains.

But as I said, there's debate on this. So consider the relative cost of chains and sprockets, and figure that extending sprocket life even at the expense of chain life is a decent trade off.