By now there are videos of people just pushing the iPad with their thumb in the middle and it cracking in half. Sure, some cheaper, large tablets bend when you press hard enough or crack when you use full force, but the problem seems to be how little effort it takes to crack the new iPad in half. While most people wouldn't accidentally crack it in their hands, imagine it getting hit in the backpack or something. The reports seem to all claim that the build quality is poor and that it actually takes little force to break it.
I only found that out after googling to see what's up with the new iPhones though. Seriously, check them out, especially the XR when you get the chance. Maybe we've been spoiled with the newer Galaxies and older iPhones, but the XR is the first iPhone that I remember that actually feels like a toy.
I mean, this is the same Apple that sold the same Mac mini at the same price for 3+ years. And has yet to update their Mac Pro in over 5 years but still charges the same. The problem with many iPhone users is that they see it as a fashion accessory or a status symbol so you'll have people that will pay S9+ prices for an Xr or whatever the bargain bin iPhone model is this time around. But you said this extends to all the iPhone models, including the Xs?
I still haven't read too much about the bending of the Pros but Apple's fetish for thinness, worse than most Android OEMs, is probably the culprit. I'd like to think they use high quality aluminum for most of the Macs and iPads but I'm also not sure that's what the iPad is entirely made of. I think so, though. So the main factor has to be just how thin this fucking thing is. The headphone jack died for this lol. And the Home button. I have yet to use a device without a home button and I'm not ready to give up the fingerprint sensor on the Home button like my S7 and the iPad Pro.