Every single binary every emitted by LLVM has been Bitcode during the compilation process. The only new element here is that Apple's asking for this intermediate product in order to be on the App Store.
Yep, and what I'm saying is that Bitcode doesn't help portability; only in producing device-optimized binaries for variants of the same ISA. The end goal here is reducing app size, not making it easier to port things to a new ISA. A new ISA wouldn't be impossible -- Apple is one of the few companies to successfully navigate this transition -- but IMO Apple would be better served on the Mac side by lower-power x86 parts (which are finally available) than higher-performing ARM CPUs.
