I suspect there would be larger deltas due to improvements in nutrition and fueling. As another poster has mentioned, today's runners are ingesting so many more carbs per hour than 20 or 30 years ago. And if doping trends have changed over time, that's another factor. (No clue either way, but it's a potential factor.)
There's been lots of research into shoes though, so you might be able to work something out. For instance Jack Daniels (the running coach, not the beverage!) found that adding 100 grams to a running shoe increased aerobic effort by around 1%.
There's been lots of research into shoes though, so you might be able to work something out. For instance Jack Daniels (the running coach, not the beverage!) found that adding 100 grams to a running shoe increased aerobic effort by around 1%.