We have gym "helpers" who are minimum-wage paid high school kids responsible for re-racking the weights and desanitizing the benches at the end of the evening. Poor little dude(maybe only 150lbs himself) has to give everything he's got to move 1-150 DB back up on the rack.
This fact and liability issue is probably why don't have higher lbs ones.
Everytime I see the owner I ask him to buy heavier dummies. The prick has a brand new truck and a huge house but his gym's dumbells only go to 120, and they're fucking bent on top of it.