One of the biggest mistakes a fan can make, is assuming that coaches know what they are suppose to know, and what they are doing. Remember, They ALL passed on Tom Brady 5 times during the 2000 NFL draft. They ALL passed on Russell Wilson twice in 2012, as they did with Joe Montana in 1979 (both 3rd round picks). Some coaches can see latent potential talent in a player better than others.
Jerry West was/is very good at evaluating talent. He traded for Kobe Bryant (Charlotte) right after the draft. Look how that worked out. They all knew about Butler, but I doubt any of them took the time to look at her play (film) during her time at UConn, or talk to any of Geno's staff. They simply went by what they saw and remembered from seeing her on TV during her time at UConn, which was certainly not indicative or suggestive of the potential she had, or the stats she's producing.
George Mason coach Milleson is reaping the fruits of Geno's labor. The things that Butler is doing, the honed skills and mindset she brings into a game, the player she has become, are ALL by-products of her spending 3 years at UConn under Geno. Milleson knows that.