Put me on the record as saying it now: You are partly wrong. Costs are not going up. If anything, they are going down. Here's the kicker: The US Dollar's value is plummeting - and it needs to. Several economists have proposed that the only way the United States could pay off the federal debt is to devalue the dollar until we have printed enough money to pay off our debt.
I think you're right about this: the manufacturing base and supply chains are much more fortified than they were 4 years ago. Production of AR-15 parts and accessories is easily 5x more than it was in 2008. Look at the number of Pmags available now and how the prices have dropped over the past year. Windowed PMags used to be $20 each, now you can find them for as low as $12 each. Palmetto State Armory has been growing explosively and most companies have been able to keep most things in stock lately.
I also think you hit the nail right on the head with this one. In Chicago last year, the only thing that prevented a local $.05/rd tax was the fact that some ammo (such as .22LR) costs less than $.05/rd to begin with. This was the first attempt of many, and this threat will not be going away.