Or in the year two-thousand-and-never, when they realize that they're better off paying royalties to the people behind the well done fan translation than being redundant and making a translation of their own or being dicks and just stealing the fan translation.

Like, a reason that they put Earthbound on the Virtual Console was because they already localized Earthbound. Likely, this Mother is an only slightly refurbished version of the long-extant American localization prototype. It wasn't much effort to load that in the shop.

They are probably waiting until 2016, when Mother 3 turns 10