You can make it harder for hearing protection to be lost in the field (or anywhere else), but the issue is that hearing protection takes an active effort to wear before it is effective. If you aren't wearing them, and suddenly have to engage a threat you weren't anticipating, there's almost no time to insert them. Alternatively, a suppressor can be left attached, ready to protect the hearing of EVERYONE in proximity -- not just the operator's.
It's not just about your hearing. Discharging a weapon around civilians, observers and others can damage their hearing as well.
It's not enough to argue the cost in dollars for treating hearing loss. There's an issue of quality of life: living with any amount of hearing loss is a lifelong frustration, if not a permanent disability. It's not as much an impact as say losing an arm, leg, etc., but to have your own issued equipment cause a physical impairment with your senses -- without ever suffering an actual combat wound -- is ridiculous and just plain wrong. If we CAN prevent or reduce hearing loss in our troops, there should be no debate.