Even in WWII, most soldiers didn't usually see the enemy they were firing at with small arms. Even if your sentiment that small arms combat is a negligible part of modern warfare was correct (which it isn't), this comment would still be wrong.

Yes, most casualties are not caused by small arms but by artillery. That doesn't means small arms are useless, they just fill a completely different role.

When fighting with small arms, the major goal is fire superiority, which essentially means firing more bullets in the general direction of your enemy than what they fire back. You will generally be firing at either known enemy locations ("A guy is in that building, let's shoot at the building.") or suspected enemy locations ("There might be a guy behind that bush"). This prevents the enemy from popping out and shooting at you so you can manoeuvre on them and use grenades or call in artillery or mortar fire. Sometimes you will hit people as well, because you are shooting at places it's likely that they are (the guy in the building eventually gets hit if enough people shoot enough shots at the building). Very rarely will you see an exposed person that you shoot and observably hit.