"plussed" Fairphone 3

Rightly so. The expectation is not wrong.
I only think vendors can’t meet this expectation for 100% of the users. They can try to get it right for a large enough majority of users so that support capacities don’t get overwhelmed and there’s no major internet backlash.

Ok, if we hang the bar to clear as low as “should not result in data loss”, everything should be fine.
Unless we’re still in Beta territory where even a “normal” update (not a major version upgrade) could get somewhat close to data loss.