Yeah, those things get lost pretty fast.
What really makes your ear ring is unexpected fire from your buddy leftside of you while manning a foxhole, but it doesn't last long.
Using a Carl Gustav makes you deaf for a hole week, plus the blast is so heavy that you loose orientation. (same effect like hitting someone with the inner sides of your hands on both ears).
And those really good plugs cost quite a lot, to equip 10.000 men you need about 50.000 on Stock, just for one combat week.
On a range, one can use plugs plus the hardshells over it, the stops any sound less than a nuke
I once lost nearly all my earplugs in a company-level, live fire training excercise, with mortars and Close Air Support (7.62 Miniguns on Bell 206) 4 MG74 and 2 Carl Gustav Providing cover, just whith my firing side protected. After that I had a ringin tone (=tinitus) for about a month, having to run around with earplugs all the time to relax my ears.
I do not want to know how deafening some hours of arty preparation can be... BUT beeing deaf is a hole lot better than beeing dead!