I'm pretty certain that specific parts of a phone (especially the middle) won't experience that much pressure exerted solely on that side if we talk about real-world conditions.
If anything, what people have told me is that if you put your phone in your back pocket and sit on it, the pressure is distributed all over the device rather than a specific part.
This is why you don't see every phone bent in such a way caused by tight pockets. It's hard to bend a phone like that unless you either;
1) Purposely exert that amount of force with your bare hands if you're strong enough
2) Put it in that machine
It's not impossible to bend a phone but it is pretty much impossible to do so unknowingly.