All my life, for most kinds of clothes, like shirts or jackets, buying the standard sizes has never been a problem.
On the other hand, I have never found trousers in a standard size that I would find comfortable. I have always worn only either completely bespoke trousers or standard trousers that have been customized for me by a tailor.
Unfortunately, where I live tailors have disappeared. For now this has not been a problem, because I still have many bespoke trousers made a long time ago. I wonder what I will do when I will need new trousers.
This is not an absolute size related problem. Many years ago, I have been obese for some years. Then I have learned to control my weight (after many failures), and for the last 2 decades I have been a relatively slim male of average height.
Despite this, I was content with standard sizes neither when I was obese, nor now when I am slim.
I am wondering why a lot of professions that existed when I was a child have become non-profitable, because the existence of cheaper alternatives today still does not seem a sufficient explanation. I have grown in Eastern Europe and absolutely everybody (except those belonging to the hierarchy of the ruling party) would have been considered extremely poor by today's standards. Despite this, most people could afford bespoke clothes of very high quality compared to what is available today and the tailors who made them had decent revenues.