To me, this is one of the most interesting things about time travel stories. Perhaps the manipulative murderer Futaba from the timeline we saw the most doesn't deserve forgiveness or a happy ending. But that Futaba has been completely erased from existence by the time travel; we have a different Futaba now, one that hasn't done anything of the awful things Manipulative Murderer Futaba did. Is this newest Futaba obligated to bear the sins of a previous version of her future self, one of which she has no memory?
I've been wondering if the author had given Futaba the power to time-leap as well. At this point, I think I know why they didn't.
Unless you want another
Higurashi ending (I don't), Futaba absolutely couldn't be given the power to time-leap back to try to thwart Yotsuha... because she absolutely can't keep the memories. The only chance Uichi and Yotsuha had, was with a Futaba whose mind isn't already twisted and broken beyond repair.
I understand why some feel the ending is cheap and/or too easy, but after time to ponder it... me, I'm glad it gives us a badly-needed parable:
The easiest way to fix catastrophes, isn't to start after the train wreck has already happened.
The easiest way to not let things get that bad in the first place.
How do you save nine people from falling 35,000 feet to their death? Don't wait until the plane's falling at 50,000 feet per minute, only a few thousand feet from the ground. That would require a miracle that feels cheap and easy in story terms. But what if you could go back to five minutes before the plane takes an incomprehensible turn straight into a monstrous storm cell, and warn them? Or better yet, admonish the maintenance crew to make sure the plane's weather radar won't leave them blind. Or slap the CEO in the head for hiring someone so inexperienced, as the copilot of an extremely unforgiving plane that will kill you if you don't have two top-notch pilots. Or slap the FAA in he head for not requiring better upset-and-recovery training. Etc.
