> the reason why developers are shackled to Objective C is to make sure processes finish in human time, and this is fundamentally a performance bottleneck in mobile hardware. This is completely false. You can get good performance with high level languages like lisp. It doesn't have to look like C to be fast and to be possible to optimize it well. The whole "writing low level code is faster" mentality is WRONG for 99%…
I read this a lot but I don't know where it comes from. For me, 'fast enough' in terms of subjective performance of an application is 'as fast as the current performance benchmark on that platform'. Anything less implies the developer has taken short cuts and creates a bad impression. On mobile devices even more so.
Sure, if your app can be neatly divided into broad sections of performance critical and non performance critical code, then you can save the C for the bottlenecks. But it's hard to know ahead of time where those bottlenecks will be, nowadays even more so with highly interactive mobile apps. Look at all the trouble Google have had making Android scroll smoothly for example.
In a marketplace where users will dismiss your app immediately over tiny glitches and pauses, I'd be inclined to write everything in C++ other than the Objective C stuff.