The army may not rely on volley fire anymore but numbers are still very important in warfare. That's why National Guard units were sent overseas.
I don't think the M1917 Browning or the Vickers either would be a good weapon anymore because infantry tactics have changed. I'm not so sure the army believes in machine guns that much anymore. But for that matter, not all armies ever saw them the same way anyhow. It all depends what you think a machine gun is for and in the same way, what the infantry should be doing. At the moment they spend a lot of time patrolling in hostile cities hoping a bomb won't go off around the next corner.
Supposedly modern machine guns, beginning with the MG34, had quick change barrels to enable them to take on the role of the heavy, now called medium, machine gun, therefore being an all purpose machine gun. Well, I've never seen a photo of an M240 with a spare barrel. I have seen photos of an M60 with same but some idiot designed the gun so the bipod was attached to the barrel. No personal offence to the designer, you understand. The company I was in had one M60 and it came with one barrel. Are M60's and M240's (and M249's) ever actually fielded accompanied by a spare barrel.
Are machine gunners actually taught to shoot their machine guns single shot?