I see the "argument" as: in sports like soccer or basketball, skills like dribbling or shooting accuracy don't have a skill "cap" and are generally uncorrelated to physiology. This is compared to the skill of descending a mountain at speed, which is dictated by how fast you can actually make yourself go, which is a matter of physiology.
It's not that strategy and skill don't exist in cycling, it's that raw power output (Watts per Kg) is ultimately the deciding factor once cyclists get to the skill cap of piloting their bike down a mountain.
So basically, could I cycle down a hill at 50-70mph? Absolutely not. But among the people who can, then the competitive advantage becomes how fast you can make yourself go down that hill.