One thing I have always
disliked about rear racks was the tiny screws they're held on with. They're junk, every d*** one of them.
When I was riding bikes a lot years ago, I always carried extra screws for when the rear rack screws fell out.
And they always
Eventually the threads in the hole get chewed up, and screws won't hold anymore, so then you have to find some way to attach a bolt through there--but the trick then is, that there's often hot much room on the chain side. A regular bolt head or nut is too tall, and will prevent the smallest sprocket (of a 10-speed bike) from being used, because the chain will hit the bolt head/nut. I've put rear racks on almost every bicycle I've owned, this problem always
comes up, and I've always hated it.
In Europe it's not difficult to buy a bicycle with a rear rack that is integral with the frame (welded on) but you can't find that in the US yet, unless you get something custom-made ($$$$
) or do it yourself.
When I did the Fusion rack I spent a lot of extra time and made four clamps that fit over the frame tubes and are held on by four 1/4-20" bolts. They're relatively heavy and look clunky but they haven't come loose so far, and I am fairly confident that they will not be the first part of the frame to break under a severe load.