Palm actually did have the distribution in place - through palmgear (interestingly, it still exist) which was THE go-to place for Palm apps.
Regarding advantages to the software developer, having just one place where you distribute, and that place being controlled by Apple, isn't a good thing at all. It may mean that it's easier to start selling, but also that you have no negotiating power if and when your app becomes a success.
The stupid music companies managed to hand over the keys to their distribution to Steve Jobs, but they're not exactly happy about the fact that he now has so much control over their fate. Apple's great at creating consumer electronics that actually appeals to people, but they don't seem to be a very nice company to deal with as a business.
Regarding advantages to the software developer, having just one place where you distribute, and that place being controlled by Apple, isn't a good thing at all. It may mean that it's easier to start selling, but also that you have no negotiating power if and when your app becomes a success.
The stupid music companies managed to hand over the keys to their distribution to Steve Jobs, but they're not exactly happy about the fact that he now has so much control over their fate. Apple's great at creating consumer electronics that actually appeals to people, but they don't seem to be a very nice company to deal with as a business.