As a Mac user, I am alarmed by the lack of USB ports on new Mac laptops. I realize I can use an adapter, but have you considered what the future will be for this keyboard that is meant to last decades? By the time it finally ships USB may be on the way out. Or not.
PS/2 is freaking ancient and if keyboard enthusiasts are managing to successfully deal with it, something tells me we’ll be fine with USB.
The great thing about the Model F project is that the controller is open source so it can be updated for whatever the future holds. Also I have chosen to go with the separate controller board so that you can replace it down the line. You can even buy a USB C adapter if USB C is the only available port on your computer. However I think USB will remain available in the decades to come.