Now when I’m at festivals and I have friends without earplugs, I usually recommend them to just use their AirPods Pro (if they have some) instead of buying cheap plugs
For some kinds of music it is more or less ingrained in the culture -- think of the "It goes up to 11" in Spinal Tap. But in fact it's worse than that; almost all music is played way too loud.
During the Covid period I attended a number of smaller scale events, that for some reason used a lower sound volume. It Was So Much Better. Those events proved what I already heavily suspected: you do no need those high sound volumes to fully enjoy music.
[1] Sigh, actually, I am able to understand but it's just sad instead of funny: the experienced professional musicians have all partially lost their hearing from years of too-loud music. They don't trust the juniors to set up the equipment, so they tune it to their deafness level. This then damages the hearing of the juniors, so by the time they get to be senior enough to be trusted with the volume knob, they're half-deaf themselves.