I don't know what you consider "serious speeds", but wings can produce meaningful downforce at pretty low speeds. Check out the various unlimited class autocross cars which carry giants wings for downforce, even though autocross events are typically very low speed events (2nd gear most of the time).
Plus, with extreme aero, there's a top-speed vs downforce tradeoff to be made. The big fan trick doesn't have that issue.
Example: Porche Cayman GT4 RS, extremely potent track-day Porche with giant wing.
> https://newsroom.porsche.com/en/press-kits/718-spyder-cayman...
> "At the car’s maximum speed, there is a total of 122 kg of rear downforce."
Yes, thats right, you get 122kg of extra downforce once you hit 196mph. Really helpful in 2nd gear... The reason manufacturers generally only quote wing downforce on road cars at incredible speeds is because the number is not very impressive at lower ones.
That's a street car. You need to look at race cars to see where wing development can go.
For an example of race cars which generate downforce at autocross speeds, take a look at cars like https://www.autoxandtrack.com/a-mod-acme-special-fastest-aut...
i couldn't find any numbers, but they do put them in the wind tunnel.
However the percent of time saved for the slower cyclist is less, but only a little.
Basically at cycling speeds the aerodynamic curve is pretty flat so it doesn't really matter if you are fast or slow.
Drag racers have had this problem for a long time; those races last less than 5 seconds. This hill climb is interesting because it's only a bit longer, half a minute, which really changes the equations for electric race cars vs. something like Pikes Peak which is 8 minutes to the top (and is now also totally dominated by electric cars).
If acceleration were an instantaneous off-on step, that would be a https://en.wikipedia.org/wiki/Dirac_delta_function
Obviously, this is wrong in the real world for so many reasons, but that doesn't stop this from getting repeated.
Everyone who's ever used a drill knows that while speed and torque are inversely related in most of a motors normal operating range you don't get insane torque at low speed. Of course you can wind a motor differently to mitigate this somewhat but still, not a huge improvement. You wouldn't see reduction gears on all sorts of things if this were the case.