Ipods and Zunes

Recently my IPOD broke, the 5th one to do so in 6 years. Tired of shelling out $300 on a regular basis, I seriously considered switching to Microsoft's Zune. Unfortunately, I discovered that the Zune is not compatible with Macs, and I was left with no choice other than buying another IPod. Who's responsible for this incompatibly? Is it Mac, trying to defend the  IPod marketshare? Or is it Microsoft, being dicks as usual?