Earlier quoted context omitted.
One problem with that is that not all the articles are the same size. You can order 1000 t-shirts in the same size from a manufacturer and not all of them will be the same size (especially if you order the cheapest you can find). This is mainly due to cheap fabrics stretching unevenly (roll to roll difference and beginning of the roll can stretch differently from the end) and if you cut them by pressing through a thi…
What if we ended up with a system where I know I'm a B29. Then after every shirt made, it's tested against the B26 - B34 (since it's probably somewhere in there) and then labelled as a fit for B29. Then I just go shopping for B29s.
Going in to a store would seem absolutely insane if you could just order tons of stuff in your size and it all fits and you would not have to make returns.