Yes, the social situation changes quite a bit, but that's a transition that everybody makes, regardless of being a star athlete or just a "Regular Joe" student. Mika likely would have finished as BYU's all-time leader in points, rebounds, and blocks - he would have been one of the most legendary athletes in the school. He could have played 2 more years with some teammates who are good friends, and maybe help BYU win a lot of games. That's the reason to stay.