In the opinion of this blogger that has been a Power Ranger fan since 1993 and have been in the internet fandom for ten years, I believe Disney wanted to a lock on the boys' market. Marvel is house of go-to boys franchise, the number one being Spider-Man. Many in the media believe Disney is weak in the boys' market and they want to tackle it. Well, they had one powerful pawn in the boys' market which was/is the Power Rangers. Unfortunately, they did not know how to wield it or/and they really couldn't wield it anywhere else. As I have mentioned before, the reason Disney has stop production on Power Rangers is because they no longer wanted to share profits with Toei and Bandai and wanted to do everything on their own and get all the revenue. Now, with Marvel, they have more avenues.
They still have to share with Marvel but it is just not one property. They have Spider-Man, the Hulk, Iron Man, the Avengers, Captain America, Thor, X-Men, The Avengers, and the list goes on and on. They can do animated series, TV movies, big movie features, etc. One non-Power Ranger fan can say Marvel is a bigger fish for Disney to tackle, a more of a sure thing. But Disney hasn't completely given up on Power Rangers, because they still have Super Legends merchandise and still have the copyright.
Now that Disney has returned Power Rangers to Saban and Saban has done a lot of promotion for the new season (Samurai), Disney has said that the reason they dropped PR was because mothers complained about the violence. But I am scratching my head in bewilderment at such a statement because the Marvel heroes are much more violent. I've seen Iron Man merchandise in Disney Store and Iron Man the movies are rated PG-13 and show lots of violence, much more than the play violence of Power Rangers. So again, I'm scratching my head as to why Disney spokespeople would say an obvious and weak excuse for dropping Power Rangers. Like Saban said, they didn't know what to do with it.