I have Traffic X installed and (especially for $30) is more than I could have imagined 20 or so years ago.....

But scanning the other air traffic in the vicinity, I notice that none of the commercial traffic at cruising altitude (25,000+ ft.) travel any faster than 304 KIAS. This can't be "normal", can it?

I understand that making landings look really convincing, for instance, would require much more effort.....but how difficult would it be to make a plane flying at altitude resemble it's true airspeed?