What makes you so sure that Microsoft will release Skype for 32-bit Linux? Linux is already a niche market for desktop computing and 32-bit installations are another niche among current Linux desktop installations, so that would be a niche within a niche. There’s really no good reason to run a Linux desktop installation for 32-bit CPUs these days; if your hardware is incompatible with 64-bit instruction sets it’s quite old and probably not powerful enough to run the new Skype client anyway.