I am not sure what you mean by asking "Why is EPS not recycled more?"
EPS or expanded polystyrene is a plastic that is 100% recyclable. Rules created to reduce the impact of the use of plastic on the environment ensure that manufacturers create EPS in a way that allows it to be recycled after it is used. EPS is used in thousands of applications, from coffee cups, to coolers to insulation for homes, etc.
A large amount of EPS made in the US is recycled. Why more of it is not recycled could do with the fact that customers do not dispose them correctly after use. For example, if people were to keep in mind that the plastic their coffee cup is made of can be recycled and they ensure it is thrown after use in the can meant for collecting used plastic it will be recycled.