I guess you missed the idea that printed charts will still be possible, just not in raster format.
Since you're in the snotty get real mode, most of us have multiple redundant electronic systems. I count four on my boat, all with independent power supplies and gps receivers. If you think I'd lose all of them together.... get real.
I second Rockter's sentiment: Get Real! You can't trust your life to GPS. Here's some "snottieness" from the United States Coast Guard:
"...it is important to remember to use all available means for navigation and maintain proficiency so you can still navigate should your primary GPS fail." https://www.dco.uscg.mil/Portals/9/D...lerts/0116.pdf
(I strongly recommend reading that Safety Alert!)
GPS is being jammed at the Norwegian-Russian border, in waters around North Korea, and in the Black Sea.
If things get "tense," GPS and Russia's GLONASS will be primary targets. There's a reason why the EU has spent billions developing their own Galileo constellation (not yet operational): satellite navigation is extremely vulnerable to jamming, spoofing, and denial of service. eLoran is not vulnerable - but the US is dragging its feet in deploying it.
But right now, if the global satellite navigation systems fail -- we are thrown back to the 19th century. https://arstechnica.com/gadgets/2017...because-cyber/
. I've been practicing for 20 years as a certified information systems security professional (Boeing, ExxonMobil, NASA). Everything I know about GPS scares me. It is extraordinarily vulnerable to denial of service.
My own chart plotters use both GPS and GLONASS. When Galileo comes on line, I'll use that too. But all those systems combined are not 100% reliable. The US Navy has resumed teaching celestial navigation. Why do you suppose they are doing that? "... relying solely on technology could be a recipe for disaster." https://www.stripes.com/news/break-o...again-1.391219
Except for fire on board, I can't imagine a situation that could cause deeper despair than loss of GPS at sea without a backup. I carry a fire extinguisher.. and, a sextant, a current Nautical Almanac, a hand sighting compass, and paper charts. Without paper charts, I can't effectively use the other backup tools.
How are you
going to navigate if your chart plotter's GPS goes keel up? Do you put any credence in the Coast Guard's advice? Not having a backup is using luck as a strategy.
I'll one-up Rockter's comment: Denial can be deadly. Get your head out of the sand!