I think we need to get to the point where regardless of the build script, Bootstrap will make the perfect foundation for a design system. I defecated to ZURB long before this was a deal-breaker, but now I almost prefer to reinvent the wheel. Getting on board is quite a commitment, compared to just wrapping react-select, or something alike.
Reinventing the wheel is awesome! More people, myself included, need to build from scratch and learn ourselves every now and then. Definitely interested in more tooling around helping folks getting started, too. Spent a lot of time on the customizing side for this release.