We are only 3 and a bit years into the line at this point with the 4th year part announced. We already know Rarity, Pinkie and Dash will be getting another FS size release this year [on top of the already releases Fluttershy]. I dont think we can say she is never going to be seen again. Sure, there is certainly a distinct lack of Applejack in general within the toy line but I really do think she will get another release at some point in the future.