"These days you have to live in (or near) the largest cities in the world"
I'm not sure exactly what you mean by bespoke tailoring. I've found small shops that will do custom work. They are somewhat rare in the US, just like custom shoe makers, but they do exist outside of the largest cities.
Also you can get a 3 piece suit custom made in SE asia for $1-500, custom shoes for $50-$100. If your goal is to have a custom wardrobe a plane ticket would save you thousands.
A lot of these guys travel - they book a hotel conference room, you go and pick your fabrics, they take your measurements, and you get your suit in the mail.
"Also, anything you bring back that you did not have when you left the United States must be "declared." For example, you would declare alterations made in a foreign country to a suit you already owned,"
I imagine myself driving across the country, and arriving at a small town to get gas and lunch. As I eat at the local diner, I become aware that everyone in the town is dressed exceptionally well, better than I am in fact, including the two homeless people outside, sitting in the street.
Turns out this small down of 400 people has such a tailor, and no Walmart, and so even the poorest are dressed quite well, with perfectly fitted suites and clothes.
I'm not sure exactly what you mean by bespoke tailoring. I've found small shops that will do custom work. They are somewhat rare in the US, just like custom shoe makers, but they do exist outside of the largest cities.