You're again referring to the market. Forget about the market and tell me why something should just double in price. You don't see car manufacturers charging double or triple the price for significantly better cars than previous generations, do you? No. Car prices generally stay the same given significant LEAPS in performance, efficiency, safety, and technology. A 2013 Civic doesn't cost 20 times as much as a 1993 Civic, and there's a reason for it.
It's not simply about "better performance". Prices can't go out of control like that, they have to stay in same ballpark even with improved performance.
Should 2 TB hard drives cost $700 million now?