The same Flying newsletter highlights FAA's rush to decommission most VORs. NDBs have been decommissioned at a rapid pace, and I can't recall the last time I saw a commercial AM broadcast station charted. LORAN was shut down by the Coast Guard a few years ago, in spite of protests by AOPA and others, the promise of an enhanced LORAN, and the very concern you raise about lack of a non-GPS backup navigation system. It's a very valid concern and has not been addressed, either by NextGen or whatever you wish to call it, or by FAA or DOT. I would bet DOD has recognized it and has something to address it.
As a techno-geek, I appreciate your feelings of more is better, but reality is that flying may soon be out of true pilots' hands if the technology keeps simplifying the art of flying. I use my iPad to provide improved situational awareness, but I get real joy in flying my aircraft on time and speed I measure based on weather and known aircraft performance and the proven VOR technology you pass off as insignificant. As pointed out, GPS is problematic and cand lead us into a sense of false security. What will those who program their way to an airport do when the computer or the system on which it relies goes black? I prefer technology in my everyday life, but when flying, there is a sense of accomplishment that isn't felt anywhere else when I am successful in using current technology over letting the electronic world continue to dictate my actions. (as I compose this on said iPad) :-)
We need to be realistic regarding GPS. True it is a good system. However, it does have flaws that are found in all electronics. It is weak, subject to outages, can be compromised ( this has been admitted by the DOD in numerous articles). There was no reason to decommission LORAN nor is there a reason to shut down the VOR's & NDB's. The FAA is not going to save that much money. If you compare the $110 million to the $15 trillion. Government is to serve the people and this is a service that needs to continue.
If LightSquared can create issues for GPS, there is no reason not to believe that the Iranians are incapable of creating similar issues. They have the drone and have told us how they did it. This is not the first time our "technology" has be compromised by "low technology" methods.
Iranians may not have needed sophisticated GPS spoofing to bring down the drone, though it might be in their interest to claim such capability.
If the drone did not have an INS as default nav source AND an automatic program to use the INS for navigation to home base in case of loss of other guidance, then all the Iranians had to do was: 1) Track the drone with radar or visually and note when the drone is on a heading toward the center of Iran, 2) Jam the GPS signals so the drone goes stupid on that heading, 3) Jam any other drone control frequencies so the drone cannot be controlled remotely and 4) Continue to track the drone with radar or visually, and pick it up when it runs out of fuel inside Iran.
Any drone you do not want to fall intact into enemy hands should have either an internal INS-return to base program, or a self-destruct program, in case of loss of GPS. The drone in question may have had one or both, and one or both failed. Or it may have had neither. An INS would add weight and cost...
I heard the Iranians just put up a couple of those LightSquared masts and sat there with outsized butterfly nets.