If the 670Ti will bring a proportional increase in performance over the 570 as the 680 is over the 580 (let's say 30%) at the same pricepoint as the 570 was launched in 2010 then it's not so bad considering that AMD offers 5% increase (7870/7850) for the same price that you could buy in 2010 cards like 6970/6950.
While I hear you and such reasoning bears out that, you really need to consider the loss of price advantages the TSMC price increase took away normally covered by a shrink.
Although Nvidia is working from a smaller part, I don't think that means much as yield and appropriate clocks will dictate price. Nvidia won't just give them a good price to be nice, they'll balance performance to how many they can deliver. Conventional wisdom would have Nvidia looking to place an MSRP of $400, and those will dry-up faster than GTX680's, while AIB customs will get priced above that, but at least will be in the market channel relatively quick. The GTX 570 supposedly MSRP'd at $330, but face it for many months the going rate of any such customs was >$350. I'd think Nvidia knowing 7870 -$350 and 7950 - $450, they target the GTX 670 right in the middle (price/perf) , if they reduce performance to get more chips they might go to an MSRP of $380 especially if they can get a volume of chips that don't need the PCB expense of dynamic overclocking. As Nvidia receives raw wafers then determine the mix, know the problems the 28Nm part have encountered going with the past track record is not going to apply.