What's the Deal With all the Fat-Guy Shirts?

This is seriously annoying me. I exercise daily and have a pretty damn good body for a guy my age. I'm not Mr. Muscles or anything, although that would be nice. I'm toned, have a flat stomach, defined pecks, and minimal fat around my waist.

You can't tell to look at me though - not with a shirt on, anyway. Every long-sleeve, button down shirt I own is big on me. My fat-guy shirts fit my neck size and arm length just fine. They also have enough room in the belly for an inflated beach ball, should I chose to stuff one in there as well. What's up with that? I'm not shopping in the fat-guy department or the big-and-tall store.

Is it a regional thing? I live in the Rochester, New York area and the majority of people in this town (over 25) are overweight. Nothing against heavier people, I'm just not one, and I'd like some shirts that fit me properly. Could it be that stores in this area generally cater to the regional standard of a predominately overweight population? I know clothing stores in different areas of the country (and world for that matter) carry different selections of cloths at the same time of year. Different catalogs, different cloths, different styles... for different weight classes?

So what's the frickin' deal? Why is it that I practically need to have a shirt custom tailored if I want to wear something that isn't all bunchy around the waist when I tuck it in?

I don't think it's because I suck at picking out cloths or anything (although I kind of do). I have my wife accompany me and often, just go shop for me. She's awesome and actually has some fashion sense, which I am unfortunately lacking. Most women tend to know how to shop and what their man will look good in. Even so, she has a hard time finding me shirts that fit properly. If they fit good around the waist, the sleeves are too short. If the sleeves are long enough, they're also too roomy for my arms and the waist is big enough to fit a pillow in there too.

Whatever. I just don't get it. So I live in an area where most of the people have a bulging gut, but I don't. Not even close. There are others too. Believe it or not, I'm not the only one who exercises regularly and doesn't eat more than my body needs. We're few and far between 'round these parts, but we do exist. So where can we buy shirts that will fit us but not also a fat guy as well?

Again, nothing against overweight people. I'm not picking on heavy people and if that's what you got out of this, you really missed my intent. What if clothing stores only sold skinny-guy shirts? See my point?