Notionally, this is already accounted for in the CPI, which, where the exact same product is no longer available, uses a similar currently available product and applies a "hedonic quality adjustment" to account for the qualitative changes.
Very importantly, CPI does not hedonically adjust health care or housing (two of the major drivers of inflation). The main categories that are hedonically adjusted are clothing and appliances.
This is a major omission. To see how glaring this is, consider a back injury I suffered in 2012. I paid a pretty penny for surgery/scans which didn't exist in 1980 [1], and it was worth every penny and more. If the injury happened in 1962 I'd be disabled in 1963, and probably 1973. In 2013 I deadlifted 1.5x bodyweight. Without a hedonic adjustment this looks like inflation.
[1] It was actually pretty cheap since I was in India, but in the US it would have cost a lot.
The former Goldman Sachs chief economist gave a speech explaining the economy's progress and the Fed's successes, but come question time the main thing the crowd wanted to know was why they're paying so much more for food and gas. Keep in mind the Fed doesn't think food and gas prices matter to its policy calculations because they aren't part of "core" inflation.
So Mr. Dudley tried to explain that other prices are falling. "Today you can buy an iPad 2 that costs the same as an iPad 1 that is twice as powerful," he said. "You have to look at the prices of all things."
Reuters reports that this "prompted guffaws and widespread murmuring from the audience," with someone quipping, "I can't eat an iPad." Another attendee asked, "When was the last time, sir, that you went grocery shopping?"
Food and gas make inflation volatile, but they don't much change the long term trend. Inflation in food and gas is actually lower than inflation in core CPI.
The big issues with CPI over the long term are the lack of hedonic adjustments in medical care and the change in the composition of the basket of goods being measured. These tend to bias CPI up, not down.
http://www.bls.gov/cpi/cpihqaqanda.htm