In the D-League, the player stands the chance of getting called up to the league. If it isn't going to happen, the eventually accept that fact and go overseasand make money there. The problem with staying in college is that the NBA now pegs a kid as a player, or not, early in his college career. Jakarr is 2 years behind the one and dones. A third year is not going to improve his draft stock unless he makes some remarkable leap in terms of skills. Sometimes a kid, such as McDermott, show more in their Jr. and Sr. years than they did early on, and improve their draft stock. That rarely happens. If the league doesn't feel you're good enough after 2 years of college ball, it is unlikely that they will draft you later on.
Jakarr did what he feels is best for him. I think he might have improved enough next year to get drafted, but that is not a certainty. Just my opinion.