A product manager that’s still running someone else’s roadmap a year in is effectively a project manager. A product manager that throws the roadmap away on day 1 in favour of their new vision is very likely a liability.
…A artifacts. I won’t go as far as to call it bullshit, but it’s not the way to succeed in software. Understand the vision, find a problem worth solving to achieve it, build a hypothesis to solve it, and then validate it as quickly as you can with real customers. Rinse and repeat.