I think the Mikunis were bolted on to get all of the orange faithful on-board with injected 2Ts
Sherco's headman is on record as saying they have a saleable efi 2T but continued to work on the carbureted bikes and are able to pass emissions with those, so they're sticking to it.
TM has had efi prototypes since 2005, but are in no hurry to bring them to market.
Then there's this article, but I'm not sure how credible it is.
http://motonew2017.com/ossa-in-2017-will-launch-a-enduro-300i/