If all you needed to install custom apps on iPhone was a toolchain, people would embed it in apps sold outside of the app store. Next thing you know theres a massive end run around the apple revenue model.

Surely there's other ways to prevent that? Like making the fee one time if you don't plan to publish to the app store.

Ah well, I guess I'll have to fork over that $99 when I want to install my own apps.

Also, if I install an app with a developer account, but don't renew it the next year, will my app still be usable, and will I be able to update it?

That was my thought but I couldn't articulate it as well as you did.

Off-topic: By all means, charge the $99 for distributing on the App Store, but I am not really sure why Apple doesn't allow for Apple ID level verification for personal apps. Something similar to the mobile provision they use right now, e.g. having Xcode generate a binary that is associated with the same Apple ID as on the iPhone.

I don't think that would work because setting up a shared Apple ID using a throwaway webmail account would be trivial. Each one would be good for multiple devices, and running a build script to generate multiple binaries for multiple accounts wouldn't be all that hard.

They used to ask for a credit card, but I believe that's no longer required (if it were, you could just use a prepaid gift card).