I have been using apple products for a long time now, and it seems that for every apple product I buy I manage to find a flaw. whether its iPhones that have scratches and chips out of the box, iPads with uneven tone of the display (one area water than the other), or a MacBook with the lid shifted compared to the base. my experience is that no apple product will be perfect out of the box, and that trying to get a replacement is not worth the hassle as the replacements as well are not perfect out of the box. and lets not talk about fiascos like the butterfly keyboard which was kept alive for way too long.
now, if it was a mid-range tech company, where the products were cheaper, that would have made sense, but the apple brand is synonymous with quality and luxury, and for the price they charge for their products - wouldn't it have made sense to accept no less than perfection? to expect more rigorous quality control?
maybe people who have insight on how apple and similar companies do quality control can shed some light on that, and on why the end result often doesn't seem to match Apples reputation?
If I am understanding your question correctly, you want to know why the apple products are not perfect?
What product have you bought in the last 5 years that was perfect? Understanding that perfect is subjective.
Where was it manufactured?
How much did it cost?
Did it's perfect add to it's performance or appearance?
People have had hip replacements that were defective.
$3.2M homes with all sorts of defects.
Boeing's 737Max had software defects that killed people.