@DoubleDD
It is all about the audience you can reach. Duke and UNC have been powerhouse basketball programs and now they are both borderline top 25 in football as well where the KU football programs at the very bottom. More importantly, they are on the East Coast with an audience considerably larger than KU.
Look at the K-State program that has been consistently top 20 in football for while now, and they have decent basketball program to boot, and yet they cannot get the contracts lesser programs do. Their audience is tiny compared to other less successful programs and hence they have no big offers. They are competing in very limited market against two other states schools which lessens the market share even further. MU, on the other hand, is located in a state with over twice the population of Kansas and they are the only major school in the state and has the lion’s share of the audience, and thus have a huge advantage.
Adidas is huge in soccer (although Nike is gaining) and soccer is the most popular sports most everywhere not called the USA, so a lot of foreign players have a much greater exposure and brand awareness to Adidas than they do Nike. I grew up playing soccer and back then, the Adidas cleats were what every player aspired to get. Its is not really surprising that foreign players favor Adidas.