as per the report, the shooter knew he was vulnerable and so had a camera to observe the hall. He was smart enough to know the game was over once they were onto his location.
This has nothing to do with weapons - and everything to do with tactics.
My point is the assumption that rifle (or auto rifle) always beats pistol is dead wrong.
Excuse me. The rifle always beats a pistol when the rifle is on the 32nd floor of a hotel a few hundred yards away. Your comment makes no sense.
The original question was why didn't a CCW citizen pull out his weapon and take out the sniper. The question was not why didn't someone sneak up to his hotel room and put a bullet in his head.
Nobody on the ground could have even seen the shooter at night in Las Vegas.