Traction (esp. on mobile) has been hard for a long, long time; it's absolutely not a new problem in 2017. Why? The competition to get and keep user attention is BRUTAL.
On one side, we've got large, entrenched players (FB, Google, etc.). And when something catches their eye, they pull it into their platform (FB vs Foursquare, FB vs Snap, Apple vs Instapaper, etc.). This puts a soft upper-bound on certain kinds of mobile ideas.
On the other side, we've got an amazingly efficient ecosystem for anyone with a $200 laptop, a free Wifi connection, and talent to build the next great app. To the first order: hosting, tools, etc are all free -- there are effectively no barriers to entry.
On the article's content, some of the charts are 5-10+yrs old, which is forever in Internet terms. It also says, "Paying for acquisition is one of the key channels still available" -- for very large national or global brands...maybe..? But if you are a startup or midsized mobile app company and your plan is to pay for customers, you need a new plan.