Another issue would be finding tracks that it would work on. Winged cars have the aero needed to run on dry and dusty tracks that the mod and late models demand. Midgets seem to work better than sprints on those tracks.
with traditional sprints it becomes an idle around the huggy pole thing and that makes it hard to draw the crowds needed to attract sponsors and pay the purses that would be needed.

Traditional sprints are growing in some parts of the country so maybe that will help USAC in certain parts of the country as long as they oversee the track prep