Isn't this also pretty much par for the course at this point? That we know going in which season of which TF cartoon is going to be its last one?
We knew ahead of time that Season 3 would be the final season of Animated.
We knew ahead of time that Season 3 would be the final season of Prime (Predacons Rising as an epilogue was a nice surprise, but it wasn't a full new season)
We knew ahead of time that Season 4 would be the final season of Rescue Bots.
We knew ahead of time that Season 3 would be the final season of Robots in Disguise 2015.
We knew ahead of time that Season 3 would be the final full season of Cyberverse (Season 4 came as a nice surprise, but was only two epilogue specials rather than another full season).
We knew that each part of the Prime Wars Trilogy and War For Cybertron Trilogy would be getting one season of their own, so we knew each would end with Power of the Primes and Kingdom, respectively.
Going even further back, we kinda knew Armada, Energon, and Cybertron would each be one season, since Hasbro kept announcing the following year's next toyline franchise with a new name.
Car Robots had already ended in Japan by the time Robots in Disguise 2001 started airing, so it was known to only have one season, too.
And even farther back, online sources made it known in advance that season 3 would be the final season of Beast Wars, and Season 2 would be the final season of Beast Machines.
I think the only western TF cartoons that we didn't already know were going to end when they did were:
- the G1 cartoon (the Internet didn't exist at the time, so that kind of online correspondence between creatives and fandoms didn't exist yet)
- Rescue Bots Academy (it was still up in the air, even to the creatives, as to whether or not it would be renewed for another season after its second season)
- BotBots (same situation as RBA, it wasn't yet known to the creatives if the show would be renewed for another season after its first one)