I can't speak specifically to men's clothing.... like pp's have said, you buy the clothes to fit the biggest part of you, and then have the other parts taken in. Which costs money unless you purchase your clothes somewhere where they're more expensive to begin with, and they offer free alterations. So *most* people don't do the "step two" part.
I know men's shirts come in the big & tall sizes. And also you can find button-down shirts (regular sizes) in a "tapered" fit where the torso is a little bit slimmer than the usual shirt, to get rid of some of that "billowing" effect.
My problem is that I'm tall (for a woman) so even though I'm slim enough now to fit a "small" the arms aren't long enough, the shoulders aren't wide enough. I end up with a "medium" to fit the arm length and shoulder width, and then the torso is too wide. Usually when I'm shopping, I look specifically for things that are cut slimmer through the torso. Fortunately, it's become stylish to wear more "clingy" clothes so I can find things that don't look like a sack on me.
the sewing patterns for men or women are based on the 'standard' proportions the manufacturers define. If someone carries their weight around the middle or their arms are wider than the 'standard', then they will find themselves going up a size and all the measurements expand a little for the larger size...so the shoulder, arm, and body gets wider as well. Women have petite, average, and tall sized clothing to compensate. Men are lucky in that a lot more alterations come free of charge. A lot of us wish that was the case for women's clothing.
when a guy shops for shirts, they have the option of collar and sleeve length. In the BIG AND TALL shops they have 3 basic proportions Big, Tall, and Extra Tall. Do the Big shirts have extra girth and allow for a shorter sleeve length, and are the shoulders a bit more narrow?
My problem is that I wear a small or extra small shirt because that's what fits my torso and my shoulder seam is never in the right place, linebacker shoulders! The seam is usually on top or inside my delts. To resolve this issue I wear a lot of tank tops, no shoulder seams!
When I was fat (at 5'6" I weighed in at about 240) I had to wear extra or 2x large shirts (tees and button downs) and I remember thinking to myself that the shoulder seams (see link) were always way over the shoulder and down my upper arm (loose) but tight in the mid-section (big belly).
About half way through my weight loss a colleague pointed out that maybe I ought to throw away my fat clothes and get ones that fit, she was right, I hadn't bought new clothes yet because I was still in denial that I was losing weight.
So I bought two new button down shirts and when I wore them I made mention to that same colleague that I feel like I look better but that the shoulder seams are still hanging over onto my upper arm. She then said that where the shoulder seam meet the sleeve seam is suppose to be at the corner of my shoulder....I then told her I couldn't find any.
Note - This next part is where some would have been "put-off" by her comment but I was not.
She said that I needed bigger shoulders to fill the shirt out.
I don't have the pic anymore but I had taken a selfie of my arms and they were looking shapely as I had been doing dumbbell curls for about 2 months at that time but my shoulders were tiny because I didn't work on them, EVER! I didn't think that was important, hahahahahahahahahahahaha!!!!!!!!!!!!!!!!!! !!!
Now my shoulders are big (a little bragging doesn't hurt) and I fill out the shirt pretty good but I now notice men wearing shirts that have the same thing happening to them as I did for me back then, saggy shoulder seams.
Question: Have you ever noticed on men or women? Is there a clothing issue you use to have with yourself that you no longer have because you're in better shape but see that others have?