@rkomar,
What you mention seems very plausible too, but I wouldn't say that this makes the possibility of dirt grains in the inner frame destroying the display less plausible.
As a matter of fact, it does even sound alot worse what you mention, since its even harder to protect the screen then. And all of this possibilities come back to bad build quality
And what good is a mobile device you cant even carry around in your backpack (even if its in a cover)