Since 2004 there has been very little meaningful change. Productivity has fallen despite the smartphone. You might be wondering why this info on the smartphone all of a sudden? I’ve received a critical mass of research. I believe that it is telling us that the smartphone is a double edged sword and we need to respect that.
Planet Money explains our period of falling productivity: http://www.npr.org/sections/money/2017/05/19/529178937/episode-772-small-change
This article explains the psychology of the smartphone and how it has made us less intelligent and is responsible for poor social skills and the gullibility crisis:
https://www.wsj.com/articles/how-smartphones-hijack-our-minds-1507307811
However, it could be that it takes humanity 50 years to adopt the changes enabled by the smartphone. Take the story of electricity. It took nearly 50 years from the light bulb before the economy showed a productivity spike. More on this via the history of the dynamo: http://www.bbc.co.uk/programmes/p057xsl0
Update 14Jan2019: Wall Street Journal article on the start of the waning of the smartphone: https://www.wsj.com/articles/the-big-hangup-why-the-future-is-not-just-your-phone-11547269202