We will keep having this debates about shoe tech. She ran a lot of rans barefoot so any shoes are like doping, much like living at altitudes or living in a warm dry climate.
I respect her opinions on shoes and our running group we discussed in detail too with equally opinions.
The moment you move away from barefoot everyone will have a biomedical advantage in shoes. Including spikes you also include a grip advantage we bigger gains.
Simple test of how much advantage shoes give, run 400m-800m on flat dry grass barefoot, then switch to the cheapest shoes you can find, then to premium shoes like the Pegasus, then repeat in the vaporfly or any carbon plate, then in spikes.
Most will find they run slightly slower barefoot (as they are not use it and that distance want do anything harm) the cheap shoes a few seconds quicker, the premium slightly slower, the vaporfly slightly quicker than the basic shoe and spikes double figures quicker again.
Increased distance is where the cushioning and biomechanical advantage will be sort mainly because we are not physically strong namely since a young age we have not be physically conditioned to deal with lack of comfort of our “easier” lives brings.
I’m glad limited are in place but it’s never been a level playing field. Plot the successful/average/best races times by runner height and you see the trend too. Let alone any coaching, diet etc a runner could choose.
With these more efficient and cushioned shoes these levels the playing field in respects to fitness and race tactics rather than all the other metric you wish to choose from that a athlete has.
We could also have the same discussion on coaching an athlete has and the training method and how can we compare athletes from the 50’s through to now which if trained differently they would be faster/slower etc.