You don't have to go to milsim to not be able to carry an entire armoury of RPG-actually-full-blown-missile-launcher, grenade launcher, assault rifle, sniper rifle, DMR, submachine gun, multiple sidearms, plus various other alien weaponry, each complete with enough ammunition to fill an 18-wheeler trailer if desired to be stored with any sort of safety.
It was fine when I was playing Doom ][ but that's something that started bothering the hell out of me back when Half-Life came out with its believable sci-fi setting, as it kept breaking my suspension of disbelief.
"Can carry only two, maybe three tops with sidearm" seems to be the rule these days.