Inoue's team mentioned before that they will take 2 to 3 title defenses and then they might consider moving up again to 126. I am also expecting Inoue to move up in weight next year.
The difference though is Haney is still young and he just moved up in his second weight division while Inoue already is 6 divisions above once he enters 126. But it should be doable. However I guess 126 is Inoue's final division as he is already in his early 30s. It will be more risky to continue moving up in weight while fighting bigger and heavier opponents.
As long as the boxer can take his power in the higher weight category that's still fine, it will only be stopped once they can hurt their opponents in their new weight division, like in the case of Canelo against Bivol, so Inoue can challenge himself and go further, until he is stopped by one of the top boxer in that division.
We don't know how far Inoue can go because he is a very disciplined fighter and he has good skills featherweight will be the most challenging division, when Pacquiao was campaigning in the lightweight I thought he could not hold out but he proved that he was an extraordinary until he reaches the super welterweight.
Even if he is so discipline, his body has limitation as how far he can get it to mature and put added poundage. Manny is very different, it was like his genes is build for boxing. I will agree that maybe at 126 lbs, Inoue could have pushed his body already.
But let's see if he moves up in that division and see how his performance is. Maybe there is power still in both hands, but the competition is obviously getting harder and tougher and at 5'5 in height, he could be physically at a disadvantage.