I come from closer to your view. People learn when they want to learn and people are very curious, especially little kids. If he's not interested in learning drums, there probably is something he is interested in learning.

Another thought I have is that you and your wife don't necessarily have to come to the same compromise position. If your approaches were contradictory, that would be a problem. It doesn't sound like they are in this case. If one of you is the voice of being a little laid back and the other wants to offer performance incentives, that seems fine.

When I was little my parents insisted I learn an instrument. It was year after year of wasted effort and arguments. Sure, I could play a song from a music sheet, but I never learned how to really play (as in compose/improvise), I never enjoyed it, and now I've forgotten pretty much everything.