re: So....Leonard Fournette recently ran a 21.78 in the 200m.

Fournette ran a 10.68 in the 100 meters. Here is a conversion from the 100 into the 40 ( LINK):

10.2 --- 4.34
10.3 --- 4.38
10.4 --- 4.43
10.5 --- 4.49
10.6 --- 4.54
10.7 --- 4.58
10.8 --- 4.63
10.9 --- 4.75
11.0 --- 4.85

I think Fournette has improved his speed since he posted that time and he would consistently run in the 4.4s. At his size, that is scary.