I'm not really sure how this anecdote is relevant. Are you denying that flash drives fail? Are you endorsing not having a backup plan?
Just to offer a counter anecdote, I had a flash drive fail with my kdbx file on it and it was a monumental pain in the ass to recover from because I didn't have backups. Have backups. Especially for critical passwords that lock you out of everything. Flash drives do fail. Statistical failures SPECIFICALLY mean that some people will not fail, but that doesn't mean failures don't happen or that they're unlikely/uncommon.
I have backups, thank you. My kdbx is in my Nextcloud, synchronised across my 4 PCs and Mac and my phone. So I have 6 copies (one on Nextcloud, and one on each device) at any time. Then I have backups on secondary storage (like external drives).
I only have very low end flash drives (like the free ones you get at trade shows) fail on me. None of the decent ones I've bought (Kingston, generally) ever failed. I still have my various 4G, 8G, 16G, 32G drives I've bought along the years, all still work fine.
The only one that failed were used continuously plugged, or to write a lot (like recording audio), and very low-end with that.
It likely failed due to the nature of its transit (in my pocket, with my keys) but that's kinda the point. I think it's worth pointing out to those who haven't really investigated your "always plugged in" is the known failure of flash drives. Flash storage does has a fairly well documented write/erase cycles in the realm of like 10k-100k cycles. While the data should still be readable, its pretty easy for bad controllers and bad filesystems (most flash drives use fat32 which is a bad filesystem) to fail a write and corrupt data.
I think the main issue I have with a "do it yourself because you can't trust the cloud" mentality is that this advice usually comes from people who have done their homework as you have. It'd be dangerous to apply "just do x" advice without those conditions as it's a bit more nuanced and it can really put people in bad situations. I've seen this same thing with people who use a NAS over cloud storage and then it fails and they discover just what the monthly cost of cloud storage actually paid for. It'd be like telling home owners "just don't have a fire" and instead of paying for insurance, but not talking about the money you set aside and fire mitigation systems you invested in.
For longevity a CD / DVD might last longer, but even then those are 30 years on average.