Why doesn't the US military use canteens anymore?

You get issued both. No one uses them and no one boils water or cooks food in the canteen cup. This isn't the 1950s. We have these magical things called MREs.

I assume because canteens don't hold the same amount of water as the Camelbaks and because if they're half full the water makes sound as you move around. Plus, you don't have the handy-dandy tube that you can get the water from.

Maybe in a setting that required their use, I'm sure they'll bring them back. One where there are biological, chemical and nuclear radiation around. The caps on the canteens have a little opening that a tube from a gas mask can be inserted into to get water without contaminating it (or at least that's the general idea).

EDIT:

They're still standard issue...but Camelbaks are a better alternative unless dealing with NBC type environments.

Right across the time of the Viet Nam struggle. Front line squaddies like the fact that they do not need to fear a couple of metallic 'clunk' when the steel canteen strikes some thing.

Private Contractors deliver pizza burgers and soda pop to them.

PRIVATIZE!

Capitalism, it makes a profit.

what do you mean we use canteens still. i have one in my barracks room right now.