Unfortunately, there's a cost. My understanding is a sniper rifle chambered for the .338 Lapua is only good for about 1500 rounds before requiring a new barrel, whereas a .308 can maintain sniper level accuracy in excess of 5000 rounds.
The military don’t have to worry about costs. I couldn’t afford it in the first place.
Which is why the AW design incorporates simple barrel removal and replacement as a design feature. It's not exactly a *quick change* M60 or MG42 machinegun barrel changeout, but it's operator do-able.
You are correct on the barrel life with one exception. I use Mike Rock barrels on my long range guns. I know of more than a dozen .308 rifles with 5R barrels with more than 100,000 rounds and still shooting sub 1/2 MOA.
We’ve been testing the .338 and one person has put over 9000 rounds through his and is still maintaining sub 1/2 MOA.
The key is to not run the gun with projectiles over 3000 fps. I use 300 grain Matchkings running around 2800 fps. Very accurate (past 1800 yards) and the barrel life is prolonged greatly.
If you shoot a lot, get a Mike Rock barrel or have Mike barrel your gun for you. You won’t be sorry.
google Rock Creek Barrels for contact info. Tell him Mike in West Virginia sent you.
Mike