Well, you're partially right.
Subs were certainly not able to match surface units in an open sea combat, although homing torps are historical, in ww2 Germany used homing torps for their submarines.
You kinda forgot that it's a game, if everything in wows was historical this game wouldn't have any sense, for example if aiming system was historical, bbs would probably score 1-2 hits per battle, if ship armor was historical, then Yamato would be invincible to any shells ingame, if cv's were historical then after about 4-5 plane attacks they would run out of functional planes, if amount of torpedoes was historical then dds could go for 3 torpedo attacks at best, and then they would run out of torps.
It's just impossible to make such a game historical without losing the gameplay element.