This is my favorite cadence video. Lance v Ulhrich time trial. I think we can assume both were doped so let's take that off the table. Jan is much more muscular than Lance but I am sure that Jan can spin any cadence he wants.
One thing we know for sure is that at the same speed Jan will be producing more torque with his legs than Lance assuming that each racer is approximately the same CdA although I suspect Lance's drag coefficient is lower than Jan's.
Lance was dating extremely well at that point in time - Cheryl Crow. Maybe high cadence will increase ones access to better girlfriends/boyfriends too.
All I know is that all the coaches I have used have valued the ability to spin fast and leg speed is a great tool to have in ones toolkit. And I have to train to spin faster but I can always elect to spin slower.