Plastic needs to be injection molded, which requires a high MOQ to be cost efficient.
Acrylic needs low MOQ, as does CNC milling
Layered acrylic is cheaper because plastics are cheaper than metals.
Metal can be anodized to get different colors
Plastic can be processed in many more ways than just injection molding
Acrylic doesn't NEED low MOQ. It the fact that it's a sheet good that can be laser cut/2d process makes it cheap.
CNC milling often requires HIGH MOQ to be cost effective.
Not all plastics are cheap than metal.
Not all metals can be anodized
If you can't accurately answer a questions, just keep quiet in the corner with the pants on your head.