The rate of growth as measured is slower. Example: Assume Netflix lacks the cash flow that Blockbuster had but provides better service - you don't have to drive to take the movies back.
This means there's more consumer surplus but it's harder to measure.
I really find that hard to believe, and historically real growth has averaged about 2% year over year. Just because it has had short-run highs in the 1950s and 2000s does not mean that right now is abnormally low.