You have to look at the bigger picture before you make a claim like that. Look at the total numbers of iPhones sold in any given year and you understand that some imperfection from the manufacture process will pop-up. This happens in any industry. However, if you come to a forum such as this you’ll think that there is such a widespread problem you will then make an error that many more issues are prevalent than they really are.
You had some bad luck, but for me and many others we have never had a problem with the Apple products.
PS: Then there is that post that you made about a spider on your screen that may have caused a scratch. Believe me that was an eye-opener for many of us on this forum.
I think being DOA would be oe ting, but also problems which crop up as well later..
eg. the number of "programs" Apple has for eligible returns due to some issue... There is a program for just about everything, except the iMac.
Quality Control also includes this as well. even if only some models are affected, It doesn't matter, its still QA. While nothing can ever be perfect neither, Apple is also not learning its lesson by it.