Dude, Laconian - iOS 5 already enables GC (a generational one at that), which already came out for regular Cocoa in in obj-c 2.0

You can bet your socks a lot of devs for typical iOS apps will be using GC.

I dunno what GC algorithm is used for MacRuby, I don't see how the upper limit of performance will be much different since obj-c uses dynamic dispatch the same, and Google/Mozilla is making strides in type inference.

Dyanamically typed languages might be pretty close to static language performance (with properly written code since the JIT is still dumb compared to a human) pretty soon.