I bet if BB's were as expensive as paintballs you would see alot less "support" players.
Also on that note alot of milsim crowds won't let someone with an AK47 and a hicap be a support player, they have to actually have the support weapon.
Throwing a box mag on a g36c and calling it an MG36 will get you flamed.
On another note how ever there are alot of easier going players around too. Referred to as Film sim. They are normaly the ones that will be on, you guessed it, film so thats why you see them more on youtube.... and they like to feel like Rambo with a ton of ammo and *kill all the bad guys*.
I have played with both, they all get hit the same. Tactics over ammo capacity.