In some cases I agree with @DrNefario. Their expectations were more on the wishful thinking side
1)These users may not have fully done their 'homework' before purchasing.
2) When #1 was done with diligence, it may be that the 'specs' were a little
vague in that area (for a reason?).
Then there was the more traditional
Lemon issue.
My first generation Astak PP would not connect on any USB2 port. (the clock would also reset on power off). The replacement was not much better in that it would connect, BUT not toa system with an Intel 82801 chip . I bought a second, Closeout sale unit. That one (2nd Gen?) did not have the issues that the first batch did.
OTOH Look at all the Calibre/Sigil 'Won't run' on 'OS...' reports showing at the same time as there are many
happy users running it on the same OS
Gremlins and interactions
It just seems, that these same users are not great at researching and troubleshooting issues.