Really? You're still griping about this? Move on to a different rifle - Ruger obviously doesn't make one for you.
I'm thinking about a getting GSR, and I know the cost of mags going in. It's a rifle that I want, not one that I need (If I had a specific need to fill, it would be filled by a gun with a narrower focus, not a general purpose gun like the GSR). I'll probably take the stock 10-round, buy a couple of fivers and call it quits. It's a bolt rifle, not one I'll likely be plinking with, and if I do plink with it, I won't be in any hurry so filling a mag in the field won't be an issue. If the mags are reliable and durable (which they are by everything I've heard), I'll never need to replace them. .308 ammo at >$1/round will be a much higher cost over a couple year's time.