So, according to this logic, if you take your new Lexus to a non-dealership repair shop and they put non-factory aftermarket replacement parts on your car, Lexus is liable when something goes wrong?
You're not getting this.
Lexus is NOT liable when something goes wrong, absolutely correct there.
However. The car should not simply STOP working as soon as you use a non-Lexus part - btw I cannot think of another product that would STOP working with a third party part.
I repeat: this is NOT about blaming Apple if it goes wrong. That is not Apple's fault. It is about the fact the iPhone just STOPS working regardless.