Gillen was leaving the books at the end of his UXM run so he had to make Scott salvageable for the next writer/era since he wasnt going to be benched. He talked about his original plans had he stayed years ago. Here's an excerpt from that:
https://bleedingcool.com/comics/kier...d-write-x-men/
Scott continuing the schism, but moreso – I was more comfortable with Scott as a "bad guy", by the end – I was going to have them in Asteroid M to really lean into it. Emma staying on the team despite the fact she and Scott were no longer together, and lots of tension here. End of the schism for me would have been a confrontation between Scott and Logan's sides, which Scott wins, and then Emma stabs him in the back at the worst moment takes Scott's whole organisation (and trainees) away from him, going full "villain." I half imagined her own school in Latveria as her new status quo. Scott was a weakling… and he'd made her feel weak. For my idea of Emma, that was entirely unforgivable. Emma is nothing if not her pride.
Gillen is a good writer but on paper, it doesnt seem like Scott would have fared well when all was said and done. Given the rhetoric at Marvel at the time, they'd probably had let him do this had he pitched it