I think it's just that 2K players don't know how to utilize small ball lineups and expose big plodding centers. Small ball lineups aren't universally better - you need the right personnel. Most players I see in 2K don't pass much or drive and kick. Also I think 2K gives bigs more of an advantage on rebounds then you'd see in real life. If I don't have another 7 footer on my team, I often pull down more boards than the rest of my team combined which inflates the value of having a giant center.