IGN has contacted Hasbro regarding the sudden removal of Transformers Video Games from various digital marketplaces. The answer they received is as follows:
Hasbro confirmed to IGN its contract with Activision to publish Transformers games has expired. However, Hasbro is not at this time discussing what, if any, plans it might have for Transformers games on PC and consoles in the future. Multiple mobile games, including Transformers: Forged to Fight, are still ongoing, however.
The aforementioned contract began back in 2006 in conjunction with the first Transformers Live Action Movie. It was previously held by Infogrames Entertainment (part of Atari Inc.) untill June 2005.
Activision has not replied back to IGN as of the time this news post is live.