Excellent article.

But despite the plane's clean and bright appearance, the family only noticed the glaring absence of seat-back screens. To them, our 737 might as well have rolled off the assembly line in 1984.

Newer technologies will allow passengers to stream content directly on their own devices (for a price, obviously).
Newer planes are coming without any screens.

One sentence above is in the future, the other in the present. That's the thing: we're in a transition period. The streaming technology is not there, yet some airlines already roll planes out without the cost (and weight) of TVs. 

As it stands, I simply always bring my own entertainment, just in case (because, also, many planes in the US still have CRT TVs, which is equals no entertainment).

I guess it also means that we shall be back to looking at attendants for the safety demonstrations.