At what point will SP going 6-plus innings be the exception?

When will we see the evolution away from Starting Pitchers going 6-plus innings, and teams start using Openers much like they do with a closer?

We have now seen the pitch count become one of the most relied-upon stats for tracking pitchers, along with spin rates and movement in the horizontal and vertical planes.

I hope I am overthinking this, but it feels like the era of Pitchers going 6 plus is going by the wayside, and that TP means more than IP.