It seems like while the Treatment IS hypothetically possible to reverse, the mental changes completely override any desire to do so pretty quickly (especially considering they’re the first changes to happen). And canonically, everyone likes SOMETHING about what the Treatment gave them, even if it isn’t quite what they wanted. Cameron and Brandy are good examples.
Cam is clearly irked about being a Faux Cow when we first meet him, but it’s more because it made catching varmints nigh impossible for him as opposed to actually full-on hating his variant. In all his sex scenes, he definitely enjoys being a sub, and he still has the perks of a big dick and plenty of virility. And he’s definitely a cute lil boy charmer~
Brandy is only bummed about the Treatment interacting with her older mods rendering her functionally mute, but she otherwise loves it (and she doesn’t even mind her form of mutism once you’ve bonded with her enough, regardless of whether or not you decide to date her).
So imo, I think any desire to remove the Treatment is from an OOC perspective on the player’s end. IC-wise, we wouldn’t want to have anything reversed because we’re happy with what we got. Basically same reason once you’ve maxxed out Ardia’s dominance on you, you don’t even want to be cured of your dzaan addiction. At that point, you’ve already firmly made your choice, and that’s further locked in by the mental changes.