Well in order for a debated about heavy assault guns and fortification to begin one has acknowledge that:
1)Assault guns exist
2)fortification exist
Some people seem to have trouble accepting it although the evidence is there. You can disagree with the rest of the OP is you like...
On the other hand, are reload bulletins better than accuracy or cooldown bulletins for small arms?
Because it's freaking irrelevant.
Call them bunkers, fortifications, field defenses, emplacements, whatever you please. Yes, they are here, some doctrines/factions use them more than others, they feature in the game, but they're not fortifications as they were used in WW2, IE to deny an area to the enemy unless they used heavy and specialized firepower. They are speedily buildable defenses that shore up your line and provide support fire if you need it, and are in no way as crucial in the game as they were in reality.
In the same way, assault guns feature in the game, but they aren't used exclusively as fortification busters like they were in real life. In-game, the Stug is a anti-tank platform first and foremost. The Sturmtiger is a blob buster. The Brumbar is an anti-infantry unit. The ISU-152 is a multipurpose long range direct fire unit. The IS-2 is a heavy tank meant to engage infantry and vehicles head-on. So on and so forth. These units also serve in a pinch when attacking defenses, but it is not their primary purpose, and damage bonuses against them are of marginal use at best. It's why no one uses the Brumbar.
In the same way, basic footsoldiers feature in the game, but aren't used like in reality because fights happen at 30-40 meters max which is night on pistol and shotgun range in real life, and standing in the open for a few seconds at that range mean you will be killed rather than tickled as it happens in-game. Yet snipers can barely fire above that range, and in game serve as offensive mobile units that pick off one unit after the other while in reality sniper were mostly defensive unless they hunted officiers.
That's what people have been trying to get in your skull. Yes, those units are featured. No, it doesn't mean they are used as they were used in real life, because this is a game made for fun and balance above all. ''Realism'' is only useful insofar as it serves as a backdrop for the WW2 setting, so you won't start to see laser guns or Orcs charging in with swords. If balance and/or fun doesn't demand that a unit behave realistically, it won't. Or do you think Soviet Penals were given SVT-40 and flamethrowers and told to ride around burning stuff in an M3 IRL?
I gave this topic more attention that it probably deserves, but jeez you really can't understand this on your own?