That is a bit hyperbolic. Some of the things they made would not make a grade with several other well known manufacturers.
Taking cameras/lenses aside, let me just point to one item: the later version of extension bellows, the auto version. It works fine, overall I would say an excellent design, except bellows material is made of some sort of double layer that separates over time (not saying all of them do, but there are plenty of examples for sale with this exact issue on full display). Once that happens they are nearly useless, short of continuously checking if manual pushing it back into shape is still holding up for a shot, as inner part goes inwards and obstructs optical path. If they were that perfect they would have chosen different material.
This is just one of a few items I could point to. Only a proof nothing is that perfect. I can appreciate a number of things Hasselblad made, they also committed some engineering boo boos. None of it would distract me from appreciating the system, even if I would certainly stay away from buying some of the accessories had I known more about them.
The only issue I had with their accessories was, indeed, the quality of their later 'faux-leather' stuff.
For instance, I had a small camera bag, the one with a zipper to hold one camera-with-lens, of which the plastic covering pealed off within a few months, the same for some lens pouches.
The bellows of my auto version didn't degrade, but it was one of the first that was sold (1983), nor the bellows of my Flexbody and the lens shade.
I think that the quality of the external supplied goods wasn't always what it should have been, Hasselblad didn't make these in house and, in the '80s—'90s, plastics weren't what they are today, which is indeed what we encounter now (and complain about).
Linhof encountered the same problems at the time (eg. the Kardan GT bellows), and the same for Nikon who's rubber/faux-leather covering of their body's and lenses degraded rather fast (eg. the D800).
And see some nylon made gears in other apparatus (eg. enlargers).
Time will tell what happens with the today made materials.
But, yes, you are right, nothing is perfect (nor humans)!
BTW, don't forget that the remaining of solar protective cream (or any cream alike) on your hands can be very destructive for these materials too, like the steering wheel of a car (ask FIAT!).