You guys are looking at this the entirely wrong way. Just because kids that you see at the local courts are wearing predominantly Nike or Adidas or UA, doesn't mean squat in the recruiting world. Specifically for basketball, it's all about the AAU circuit. These brands compete for affiliations with major AAU teams and those affiliations matter because it allowed the brands to basically start spoiling these kids from day one. Also, if a team is UA (for example), many of the AAU tournaments that they play in will be UA-sponsored tournaments, allowing even more exposure to the brand. That's why these connections matter. UA has done an astounding job on the basketball circuit and having exclusive rights to the McD's All-American game is even more positive exposure.
Football is a little bit different because it's driven by high school football as opposed to AAU, which is more like exclusive, private teams. But once again, that same All-American game affiliation absolutely helps. As does partnering with major football schools like Notre Dame.
I'm not telling you that UA is the be all end all and the best choice for Rutgers (money certainly plays a big factor here too), but these affiliations are strategically important and carry more weight than just seeing people wear that brand.