Aside from the components physically degrading (or environmental factors like radiation), I've never heard, read, or experienced this issue. Why do you believe this SD card would be susceptible to data loss after as little as six months?
This is something I never realized until I worked on an embedded system where every bit error showed up as a log message. It made me think, "how can computers work at all"? The answer is math and abstraction layers that work a little bit better than the average web framework.
The failure modes of FLASH are well-known, they dont necessarily need abstraction layers and they do work very well and reliably.
There are many abstraction layers involved. For example, your Linux application isn't bit-banging the NAND chips directly. Your SoC knows there's flash attached, and handles it accordingly. Or, the Linux MTD layer handles it. Then, there are the flash-specific filesystems, like ubifs.
All in all I find it pretty interesting, because if you "echo foo > /dev/mtdX", you're not going to find any sequence of flash cells that contain the bit pattern 0x66 0x6f 0x6f 0x0a for very long after you do that write. And yet everything works anyway. There is a _high probability_ that you will be able to read it back, but there it's never guaranteed.
Nothing is ever guaranteed. All we can do is increase the probability of success.
I can't tell you how many android phones I "fixed" for a couple years by replacing the SD cards. I actually had a sandisk 128G fail on me a couple weeks ago, that was just sitting in a dell/windows tablet with little more than a few movies copied to it. It didn't last 6 months, I guess something in win10 must have been rewritting a date/time stamp or something similar to the same sector long enough that the card just started hanging doing reads until it became bad enough that windows would choke and I noticed it.
Back about 10 years ago, I had an ARM device with an SD slot that I was writing firewall logs to. The SD cards in that machine would last ~2 months before they died. Eventually I replaced the SD cards with a USB attached SSD in an enclosure, and that fixed the problem.
you have a reference for this? which aspects did you compare or were compared?
So you ECC the shit out of things and hope. Or you use less ECC, get more "checkbox capacity" on the box the consumer sees, and most people won't experience failure until they throw the device away. It's all about margins.
SSDs, even the expensive ones you buy, don't have a super long shelf life and are not what you want to use for backup media.
It's a stunning paradox that densities and adoption is growing dramatically all the while raw retention gets worse with every generation (an astonishing amount of smarts goes into mitigating media deficiencies).
I'm not too concerned (assuming the standard backups) about devices in continuous and powered-on use, but for data at rest, powered off, this is very scary.
For long life I'm betting on DVDs (refreshed every few years). Easily half of the 15 year old drives I've been keeping are now bad; copying them forward every few years is a good idea. It might be time to go back to tape, but it's expensive. Pretty much everything sucks at retention.
Lower temps need more time but can still cause loss, higher temps less time.