Uh… are they? Jay’s older now, obviously, but back in the Golden Age he could time travel with precision just by running fast along a beach (without even needing a treadmill). In “The Return of Barry Allen,” Professor Zoom admitted Jay might actually be faster than him, even though he (Thawne) had the edge in endurance.
Admittedly I haven’t read The Flash since pre-Flashpoint, so it’s certainly possible Wally and Barry have been amped up in the last decade plus. But at least in the Post-Crisis universe, the difference between Wally and Jay was no more substantial than that of a healthy twenty-something racing his in-shape grandfather… he’s going to win, of course, but not lap the old timer.