Suddenly, Apple's apparent downer on third-party iPhone software development becomes much clearer. Taiwanese moles claim the company is considering founding future iPhones on the next generation of Intel's Ultra Mobile Platform. Today's iPhones are based on ARM processor technology. Intel abandoned its ARM chip line in practice last year, but focused its efforts on its own x86 processor platform in spirit back in 2005. Since the two are incompatible, moving to x86-based iPhones would by necessity render all existing iPhone apps unusable on the new platform.
Now, Apple has managed such transitions in the past, on the Mac. First, it moved from Motorola's 680x0 family of CPUs to the PowerPC platform. More recently, it migrated from PowerPC to x86. In both cases, Apple did a good job, but the size of its userbase made putting big resources behing the migration essential.