What is Inflation
Paul Krugman notes that wage growth has slowed and asks why are very serious people worried about inflation. I comment.
Your effort to discuss inflation is doomed, because people don't agree on the meaning of the word "inflation." There's been some progress since 1923 when Reichsbank Presiident Rudolf Havenstein wrote the mortal book entitled (in translation) "There Has Been No Inflation In Germany," but not by much.
Most people in the USA use "inflation" to refer to increased prices and assume that inflation does not cause increased nominal wages. They will not be surprised by the graph. That's what they imagine when they say inflation is a problem. Most US adults would not object of told "inflation reduces the amount of goods workers can buy with their salaries." They hate inflation (considering 10% inflation by far the biggest problem for the USA in the 70s) exactly because they assume that price increases don't cause wage increases even in the long run.
Evidently the idea is that lower inflation (and they ask economists how to achieve it) means higher real wages and the same employment. Then in a sick twist the older New Keynesians (Fischer, Taylor, Gordon) argue that central banks are tempted to cause surprise inflation, since lower real wages are clearly desirable.
Most people who fear the inflation monster under their beds don't fear a wage price spiral, they don't hope for a wage price spiral. They think higher inflation means lower real wages forever which are not compensated by any benefit such as higher employment ever.
The debate is schizoid because economists and not totally ignorant policy makers accept the public view that inflation is hugely costly (assuming complete nominal wage rigidity) and also assume that high inflation is persistent and hard to eliminate because they know how nominal wages really respond to inflation.
At the moment this is all irrelevant (as you note) since core inflation is low, wage inflation is low and a higher relative price of petroleum really does reduce US aggregate real income. But the current insanity is made more likely by the general inflation insanity. Basically policy makers know that high gasoline prices make people vote against incumbents and they demand that Bernanke save them from the effects of increased Chinese demand for petroleum.