“Eventually, we’ll all be on wheels.”
That may be true but I’ve seen some 70+ year old foot launchers making it look easy. One prolific Instructor, Don Jordan continues to fly and teach foot launch at 71 years old (as of 2007).
Many pilots choose to roll instead of run for its own sake. It’s fun. There are distinct advantages, too. For flying at high elevations or doing tandem instruction it’s dramatically easier than foot launching, allows pilots to carry more, is easier on the legs and back (with proper suspension/protection) and is less dependent on perfect winds.
Most powered paragliders can be quickly mounted/dismounted to a wheeled cart, giving the pilot a choice.
See also Tandems on Wheels as it relates to adding wheels for tandems.
A powered paraglider trike (or quad) is, by definition, a foot launchable unit with wheels added. What separates wheeled powered paragliders from powered parachutes is the wing. Paragliders are efficient which is why we can use small enough motors to foot launch—but they require more pilot expertise. Powered parachutes are easier to learn but require gobs more power to plow their inefficient square canopies skyward. Elliptical powered parachutes wings close the gap with heavier PPG trikes. One trike, developed by Chad Bastian, has foot steering hookups intended to be connected in flight. That’s how powered parachutes are almost always flown—with your feet.