I wouldn't use the word "knockoffs" to describe them, but there are many intriguing Chinese (and not only) devices mentioned in the Competitors forum already. Since Nokia support Mer (which is already running on several of those) they probably don't think of it as such a big problem anyway. Given that actual competing devices exist and will keep coming, does it make much difference whether they run some variant of Maemo, Moblin, Ubuntu MID etc?