Oh, it’s not a silly theory at all. Remember, the curse didn’t work the first time and really, the wording was “the heart of the thing you love most.” So, she failed twice. For the curse to really work, Regina would have had to “put her heart into her work” so to speak. Regina loves Regina the most.
Rumple had a completely different plan way back when he made the deal with the Queen that she would always do his bidding if he said, “Please.” She figured she’d be rid of Rumple and his magic once her curse was released on FTL. So, in her arrogance, she dismissed it. Only, her curse didn’t launch – Rumple’s did. It was all smoke and mirrors when the Queen thought her curse was manifesting. Rumple probably made back room deals with others in the Realm that had everything to lose, should The Queen succeed. So, it was a con job from the get go and Regina is living a delusional life as Mayor while Rumple waits for the right “believer” to come along and take her out. He probably can’t get his hands bloody for some reason. Whether or not he will or can reverse the curse, once Regina is gone, is unknown.