I can count on no hands the number of times that a DM I've played with has reacted to a player's DR by equipping more than a couple of enemies with an appropriate weapon type. More importantly, if they're spending their money/time/spell slots/actions on silver weapons, they're not spending those resources on being stronger in general, which means that even if your DR/silver is being negated, it's still doing something - wasting enemy effort that might otherwise be spent on things which aren't bypassing your DR.

I still don't think it really saves this from being just LA +1, but it's so many levels of not the case that DR/silver is only useful for the first few encounters of a campaign that it pains me that some people are actually trying to argue that.