re: Why Aren't There Any 7ft WRs?

I'd imagine a piece of the puzzle is the fact that human bone/tendon/joint/muscle density stays pretty consistent despite your genetic height.

Meaning taller folk are more prone to joint injury and wear + tear due to the extra load/leverage without the increased durability of the parts. With football, add in the repetitious nature of a full-time contact sport and everyone going for knee high tackles on you.

I'm guessing most 7 footers don't stand too good of a chance to get out of high school trying to play football much less college. They're better off physically and financially on the basketball court.