Is everybody wearing sabatons? Hugely heavy and unweildy boots might slow you down, but otherwise it is just about what best fits your running style; most people could become faster by changing their style, some by changing the shoe. Some people will be faster with no shoes at all. Manufacturers who label one running shoe as faster than another are lying.
It's been well-known for decades that each additional 50g on a shoe requires 1% more aerobic function for the same speed, and the gains do not magically level off as you imply.
I have heard numbers broadly in line with this but I don't have the reference to hand. I think it was a single trial rather than a meta analysis of several.
I know I feel faster with racing flats on than with trainers.
Is everybody wearing sabatons? Hugely heavy and unweildy boots might slow you down, but otherwise it is just about what best fits your running style; most people could become faster by changing their style, some by changing the shoe. Some people will be faster with no shoes at all. Manufacturers who label one running shoe as faster than another are lying.