Judging by the press release of this announcement, it looks like it was BANDAI that is the main culprit in convincing both Toei and Saban to skip a Go-Busters adaptation and move forward with a Kyroyuger adaptation.
We all know how Bandai felt about Go-Busters considering their snide comments about the show being "too-dark" for the kiddies (when the show really wasn't), and those snide comments were supported by the low toy sales for the Go-Busters line.
So this isn't Saban breaking the contract agreement with Toei, this was BANDAI telling Toei and Saban that it would be a shitty investment to adapt Go-Busters before Kyroryuger.
Yes, BANDAI hates Go-Busters that much
Coincidentally, this announcement within hours before Kyroyuger's final episode hehe