The long term problem may well be the supply of displays. Chips are cheap and easy and anyone can lay down some resist on a slice then etch, deposit, package, test and ship. Once the line that builds the display is dismantled it’s pretty much over for that display.
Suppling chips and displays and all that are what dad did for decades. It’s not quite that simple for chips or displays.
For DoD and aerospace often the components chosen would go EOL as fabs changed or closed (in the bad days of all the US fabs closing down) and/or for DoD the stuff HAD to be built inside the country.
The manufacturer was usually given the option of making one final “lifetime buy” before the part number was pulled from the line card. Then they could negotiate who would store the items or they could.
Sometimes similar chips could be substituted but not often in the heavy certification worlds like those.
There were also line cards that were considered “long availability” parts because they were used by everyone in tons of products. Problem there was the fabs were often low volume and the manufacturer had to commit to buy a long way in advance with penalties for not buying the projected volume.
Anyway it’s all quite boring to anyone not in that biz but chips can’t usually be replaced in these products without triggering really expensive tests.
Nobody knows what pre-purchases Garmin committed to for repair parts on the 400 series or refurb deals with the manufacturer. Their move to a single price repair does indicate that they’re doing some sort of parts swapping at a repair facility plus replacement of anything they have component availability for to hide that many parts are way past EOL, probably.
Heck sometimes on DoD stuff the parts were EOL before the thing being made became operational. The mess of manufacturers, distributors with warehouses, and manufacturer predictions was a common topic of discussion whenever dad talked about people seriously screwing up in his work life. Ha.
He was usually trying to fix it by shuffling orders around to meet the short term needs of each manufacturer until the supply chain could get back to normal.
Or they’d say they didn’t need to make a “lifetime buy” and then call a year later asking for the part. Nope. None left. We told you that a year ago. But, but, but... we didn’t think the product would still be popular! (Or Congress/Pentagon ordered more, lots more... and everybody thought the thing was dead...) All sorts of messes like that behind the scenes.
I remember talking to him about telecom stuff once and the history of the Mitel 8870 chipset. Fascinating. Everybody used that thing. Mitel went under for various reasons. Clones were on the market but couldn’t be used in certified devices. Later California Micro made an official clone when patents ran out. Lawsuits. Insanity. All sorts of strangeness with that chip. And it was a “jellybean” component in telecom. DTMF decoder. Cheap. Easy to use. Hundreds of millions of them sold.
Oddball components for niche builders like Garmin’s aviation division if they have to use them end up with even stranger supply side stories as the products get older.