Separate your bias from your brain being able to construct a proper logical argument for two seconds and re-think what you just asserted incorrectly.
Think about it. When testing/assembling, the components are assembled/combined in a way that does not impede functionality, nor should this impact their performance down the line as such. Think about the weight difference between individual pieces and the whole (much heavier) shebang. They are not placed in a way that puts excess weight or force that would disrupt/damage their functionality. Later on, when fully constructed/tested, they are meant to be used in a vertical fashion, with only appropriate force on certain parts, namely the screen/substrate area. Again, I suggest you search around more for pertinent details so you can re-assess what you think you know about this whole process.