There are two obvious reasons that I can see.
First, the inflation measures are imperfect and prone to political influence. So, with the first world countries already struggling with slow growth and massive entitlement programs, the easiest way to keep the high levels of debt and deficit from spiraling out of control is to under report core inflation. Thus, you can avoid cost of living adjustments on pension and social security programs.
Second, the first world countries have effectively exported our inflation overseas while we continue to run trade imbalances to import from emerging countries. If you look at inflation measures in emerging countries, you'd see exactly what you'd expect from all the money creation by central banks. Even with those countries trying to manage the inflation figures, you're still routinely seeing double-digit inflation.
Beyond that, there are a ton of factors that are not as obvious to me.