I can buy a lawn mower, why should I have to rent software?
I'd rather own myself, but I suspect we've got a lot of market education on all sides to go through before we figure out that you can't sell apps for $0.99 at anything other than lottery-ticket odds.
I'm starting to become a fan of base module free/low cost + pay per extra feature.
Back in my days, operating systems kept compatibility with applications. If you want it the other way around, you'll have to pay more for the application, one way or another.
If you want to buy software, then you need to pay buyer's pricing. Almost nobody is willing to do that.