I've been involved in successful and unsuccessful platform builds. In the successful ones, I either had absolute authority or I built for the desire paths, even if they weren't the "perfect" ones that I desired. I anchored on the non-negotiables, which I kept to a minimum, and then optimized to get people on board, even if that meant deviating from my perfect vision.

One way to keep myself honest in being on the desire path was to go from win to win (win = someone using platform and being a satisifed "customer") iteratively as part of the full build. It also helps avoid platform fatigue, and ensures that should some priorities change, we've gotten some value out of the effort.