It's certainly not from sector wear blueroom, do the math, even over 6 months 10000 writes would be 55 a day. No one uses their flash drive that much. It's probably simple physical failure, they're made to be small and portable and are often used in conditions far too extreme for flexing. You'll never see it either cause the plastic and whatever PCB is present will flex just fine, the substrate however won't.
I don't even use 'regular' flash drives anymore, my main flash drive is the micro SD card that's in my phone, much safer in there, my keychain has a USB adapter in it that has a micro SD Card slot (damned smallest thing I've ever seen) it's not tehcnically USB compliant though because to safe the form factor size it is possible to plug it in upside down