If XBox 720 or PS4 support USB joysticks, pedals, throttles, mouse and keyboard, then its a great idea. How many warning pop up boxes do you make an end user go through to make sure they don't buy Aces High without a joystick, mouse and keyboard, and just the game controller? Because with just the game controller, either HTC has to make too many compromises, or the end user is going to have a terrible experience.
But in theory, this could both sell a lot of joysticks and a lot of copies of Aces High and other flight sims. Why joystick manufacturers haven't pushed it harder is beyond me, I kind of understand the HTC not pushing it side.
The number of USB ports is a non-factor. If they are buying $100+ of HOTAS, they'll buy a $10 USB hub.