yes but they come at the price of manpower and the cost of unlocking grenades and rifles besides ammo cost and lets not say that riflemen used to have smoke grenades and they got nerfed not a while ago because they countered mg's way too efective for german average mg spammer.
If you nitpick every small difference between factions in balance arguments we'll be here all day.
The faction designs are different in too many ways to count. You have to consider the whole.
HMG spam is a frustrating strategy to play against when you don't know how to counter it, but it's a very weak strategy when you do. It's barely used above mid-ranks.
HMGs need their current power level to counter high-level blobbing. If you nerfed them to obviate the need for lower level players to learn to counter HMG spam, you'd degenerate high level play into blobbing.