the CMC, Rarity, and Twilight have all reached their obvious endgame (marks, canterlot boutique, and princesshood respectively). Dash is close to if not at hers (She's flying with the wonderbolts). none of the other mane 6 have obvious end goals.
then behind the scenes we have the senior storyboard artist and Amy Keating Rogers moving on to other projects. probably nothing, but if more of the older crew start leaving it could be a sign that they're planning on wrapping up.
or I could be reading too far into things and they'll keep it going til we don't want them to anymore



