One reason why Blackberry holds leadership positions in a few markets is they work directly with the government to ensure their products don't get hit by the same import tariffs their competitors do, giving them a very significant price advantage - for example, they started assembling BB's in Argentina a while back for this reason (http://investba.com/2011/07/research-in-motion-blackberry-ar...).

In the last few years Apple has started to do the same: http://appleinsider.com/articles/12/02/24/apple_begins_selli...)