My impression is that Objective-C is pretty big (for a minor league language) in the US, but that elsewhere in the world its use is nearly non-existent.
Most places I've lived you could throw a shoe and hit a Java developer or a Windows (VB/.net) programmer, but you could set a nuke off and not kill any Objective-C programmers.
I think NeXT and Apple never really bothered promoting it outside of the US. Australia has just about the highest level of iPhone usage per head of population, but prior to the iPhone coming out jobs for Objective-C were running at something like one per N-thousand Java jobs. Now the iPhone pops up, and all of a sudden everybody wants an Objective-C programmer with 5 years experience and proven commercial success on the iPhone... well... guess what... you reap what you sow. Because virtually nobody in Australia invested in Mac programming for all those years, you now don't have a deep pool of talent to dip into.
But a similar thing may happen with Android ... anyone that didn't invest in Linux programmers is at a disadvantage.
Trust me... it was rare as hen's teeth in the US also, especially during the period after Java came on the scene but before the iPhone.
(In 2001 I found myself looking for work with 10 months' of Java experience, and 8 years of NeXT experience. I doubt anyone hiring had any clue what Objective-C, NeXT, OpenStep, EOF were. Certainly the HR drones didn't.)
Back in the NeXT days, I think interest was primarily in US/UK/Germany, with some interest in France and Japan and maybe some Swiss activity due to the investment banks.
As far as android is concerned, I'm not sure that Linux experience provides any advantage. The libraries are all standard java stuff or android-proprietary. The development tools are also well supported on all platforms (AFAIK).
Most places I've lived you could throw a shoe and hit a Java developer or a Windows (VB/.net) programmer, but you could set a nuke off and not kill any Objective-C programmers.
I think NeXT and Apple never really bothered promoting it outside of the US. Australia has just about the highest level of iPhone usage per head of population, but prior to the iPhone coming out jobs for Objective-C were running at something like one per N-thousand Java jobs. Now the iPhone pops up, and all of a sudden everybody wants an Objective-C programmer with 5 years experience and proven commercial success on the iPhone... well... guess what... you reap what you sow. Because virtually nobody in Australia invested in Mac programming for all those years, you now don't have a deep pool of talent to dip into.
But a similar thing may happen with Android ... anyone that didn't invest in Linux programmers is at a disadvantage.