I believe Smith has one of the lower B.B. IQ’s on the team.
I think it's more that he never had to develop a complex understanding of how to play the game. He just bulldogged low-level competition in high school, using his physical gifts to get wherever and whatever he wanted.
You see him trying to do the same type of thing now, and it backfiring. He tries to bully his way to the rim to attempt generally high degree of difficulty shots, and in addition to taking a lot of contact while mostly not getting calls, he has yet to figure out reliable techniques to solve college level interior defenders.
If we compare the development of Trent and Mark: Frazier's quickness gives him an asset that he can leverage on the offensive end, even at the college level. I believe this has allowed Trent more freedom to try things - to experiment - and therefore greater opportunity to learn and evolve his game. More opportunities mean more success, and success feeds confidence. Remember, at the beginning of the year, Trent was exhibiting the same frequency of reckless play and poor decision-making that Mark is demonstrating now. But Frazier's quickness allowed him to engage a greater landscape of game experiences, and thus much more effectively refine his approach to the game at this higher level of complexity (the college game vs the high school game). Mark Smith, on the other hand, has had the physical advantages he held over high school competitors completely neutralized. One of the great consequences of this, is that Mark has run out very quickly of
things to try, thus limiting his opportunity for experimentation and stifling his capacity for learning + growth. Not having the ball as much in his hands is also a major factor here. He has a very limited ability (related to limited experience) to affect the game off the ball. This further stifles his opportunity to learn and evolve his approach to the game.
A player's gameplay is like a problem-solving algorithm. Each player has a set of functions they rely on to achieve the desired goals of a game. The process of a player's growth is essentially about the constant refinement and evolution of the player's algorithm (enhancing his programming). This encompasses even physical advancements for the player, as new physical advantages allow for stronger problem solving tools and strategies. What I'm saying overall, is that Mark Smith is not a "dumb player". What he has is a simplistic gameplay algorithm - one designed to solve very simple puzzles - that is now being asked to adapt to a far more complex puzzle.
All I believe Mark Smith needs is a larger sampling of gameplay experiences in order to 1. gain a greater understanding of the system that is a basketball game, and 2. discover + establish the identity of the basketball player he is meant to be. Right now, he is far from knowing who he is meant to be on the court.