You mean the 'Validate your idea, build a prototype, show it to people, gather feedback, improve it and keep going' part? That's far from UX, and also far from marketing.. those are steps I'd take if starting a new project. BUT all those steps should be intersected with marketing from day one.
Hmm, that’s what I think ux should do, what the marketing department was doing at my last job and why they were at war