The Mac software scene has always had lots of indie developers. Let's look at that scene for some facts... The indies generally charge an upgrade fee for "major" versions, and give free upgrades for "minor" updates. Most, like Wil, do the right thing. Delicious Library hasn't had a major release in years, but it is maintained. Others (for example, in my experience "DVD Remaster Pro" and Parallels Desktop), clearly ab…
Rovio also just released Angry Birds in Space, which is a separate app, meaning they'll get new income from it. But because it's a $0.99, giving existing customers a discount isn't important.