Generally speaking everybody demonstrates the flight planning and cross country flying skills necessary for safe flight for their checkride. However, it's common for pilots to revert back to what the author was talking about afterwards unless they are working on their Commercial rating or something like that. I did my private pilot a few years ago in an airplane without GPS and I didn't carry an EFB so it was a great way to really focus on real cross country flying skills. When I worked on my instrument rating, most of those skills and that flight planning was set aside. When I started working on my commercial, I started to face the issue you are talking about.
Today, to help me get ready for the cross country portion of my commercial pilot final stage check, I did a little experiment. First I reviewed my flight plan with my instructor to verify that it meets the ACS and is also logical. I did the flight planning in my EFB instead of on paper (the way I did it for my private) since I think it's unlikely I'll actually do paper and E6B style flight planning regularly as a commercial pilot or private pilot just flying for fun. I did not program the route into the airplane's 430w, but it did give me a bit of situational awareness due to the moving map (I could have turned it off if I really felt like it, but nah, I like those traffic alerts etc. I kept track of my ETAs to each waypoint on my iPad using Forflight. Then, after a few waypoints, I turned off my Stratus 3 to simulate I lost GPS. There were a few lessons learned about what I would need to do in that instance, but generally speaking the flight planning I had done in the EFB allowed me to start recalculating my progress once I got to my next waypoint. I plan to play around with these scenarios a bit more on future flights until I understand exactly how I should do a safe cross country flight while still taking advantage of all the technology on my lap and installed into the cockpit.
This is not a trivial problem and if I earn my CFI rating I'm not sure how I will address it with my students. I need to think about it some more.