Could it be that vanity sizing is creeping into footwear? As people - I would normally say Americans, but Australia is now officially the fattest country on earth - get bigger, perhaps so do the dimensions of each 'standard' size.
They do this, but I haven't had any direct experience doing it. There was a rumour RMW were doing away with authorised repairers in Oz and asking that boots be sent back to the factory for re-crafting. Presumably they received a few complaints about some 'authorised' RMW bootmakers and decided to move it all in house.