Artillery works great, but air power is usually somewhere else. Campaign designers probably felt it is too powerful, or something.
At least the Germans usually don't have any, so the M16 Quad 50.cal halftracks can be used as very brutal infantry support. Dunno, but are 4.50 cal machineguns that better at taking out soft targets than one .30 caliber one? They really chop German infantry down, especially if it's in the open.