And the Phase One body focal plane shutter does 1/4000th . Pick your poison. The high sync is what some may need and the higher shutter is what others may need. Rather have the faster shutter myself. I have gotten around the high sync shutter for years and have much more need for the higher shutter speed. Horses for courses, pick what systems works best for you.
I personally would not switch systems because of the glass. I would switch or chose a system because of features , ergonomics, ISO limits, different types of lenses, T/S, software and stuff like that. Obviously if you need something one system has over the other than that would come into play and price of course. Each system does a nice job of producing results , just find one that clearly gives you as the shooter more advantages over another on how you work and what you shoot.