Every button down shirt I own that fits my chest and shoulders comfortably once had way too much fabric around my middle. I matched up the measurements of a shirt that fit well on top to one that matched well on the bottom, made a template, and now I buy shirts to fit my shoulders, and take in the bottom to fit.
I've always had the same problem with vests - tight at the top button, and loose on the bottom. Even at times I've had more of a gut. Strange thing is that until this conversation went from vests to shirts, I never thought to try that trick with a vest.

But back to the point of the original post, I agree strongly that it's largely a matter of off-the-shelf versus tailor-made. And now in a perverted case of art imitating life, I'm sure tailored garments are expected to fit more like the off-the-rack clothing that people are used to.