Gas blow-by definitely affects throat erosion, the reason shooting boattails tends to erode throats faster than flat-base bullets.
The question here is how much you intend to shoot the rifle. If you plan to use it as a prairie dog gun, then the barrel will obviously burn out quicker than if you use it for occasional deer hunting--or even coyote hunting. My guess is that if used on deer, antelope, etc. the barrel would last a long time.
And if it did happen to burn out, you could get it rebored to .25-35!
