The inflation rate as calculated by central banks includes a deflator value - that is, it tries to take into account quality improvements, in your washing machine, in your computers, your phones, your iPads.
Every time Intel introduces a new processor that is twice as fast as the previous one, flooding the market with faster computers, the interest rate is lowered, and money is printed, to ensure inflation after taking into account quality improvements, remains at 2%.
The central banks ensures the populace's savings gains none of the advantages the progress of technology will bring. If they bring lower prices - money is printed to ensure prices of everything else rise. If they bring better phones - money is printed to ensure prices of everything else rise such that the benefit the consumer will accrue is eliminated, plus 2%.
