Government agencies at every level have to. It is considered granting equal access to all. So, with things like ADA compliance, it wouldn't surprise me if that is yet another hurdle with fees for licensing and such associated with it that the government begins to require for businesses. It isn't that big of a stretch unfortunately. Businesses that survive and become financially successful do so in spite of the government.
In Okinowa about half the signs are in English, also. But, at least half the population there are American military.