Lets say I went to grad school to do "A" but didn't have the entrepreneurial vision at the time or had visa/family issues to worry about to turn "A" into anything significant. After grad school, I got a job offer from a big name mining manufacturer to do something remotely related to "A" and have since spent close to a decade, only rarely getting to do "A". After seeing how things happen at Big Corp., as well as being in an almost burnt out state with Corporate, I have decided to go about my own way. However, recently, a gap has been created for people who can do "A" in the org. So at this point, is it better to switch to the team where I'd be doing "A" while I work on my pet project/future startup in the same area, with work that is overlapping ? or just stay in my current position doing "B", which I don't enjoy, but have gotten good at, while working on my own side project for "A". (FYI here "B" is Time-series Data Science/ML/prediction/prognostics while "A" being Robotics/Perception/CV research.