Perhaps by being a style icon himself?
AFAIK, his fame is partly based on making the shirts for Michael Douglas in Wall Street.
Not to revive all of the threads where this question was debated for an endless amount of pages, but my understanding is that Kabbaz doesn't really believe in hand stitching because he doesn't think it makes the shirts any better (I think he only sews the buttons by hand?). My understanding is also (from the limited amount of firsthand experience with his shirts posted on the forum) that the machine stitching is far and above better than any other machine stitching (although I guess you could think hand stitching is better), and many of those who have tried him and other makers believe he is the best, even with all of the machine stitching and whatnot, although some aren't willing to continue paying the increase in price from the "next best" (whoever that is). However, I will probably try someone like Matuozzo if I get around to visiting Italy in the winter, to see what I actually like better.
He can get away with it because he has enough clients who are willing to buy them at that price, and he doesn't need to scale up as he's content running a smaller operation.
Only 2-3 weeks if you don't get DHL. The making time is usually 4-8 days, and DHL is 3 day shipping.
I mean, I've had an ongoing email discussion with Alex and read some of his own postings and articles in addition to what you mentioned. How else am I supposed to judge, until I actually have a shirt made? This actually ties into a bit of @kulata was talking about (trusting your tailor)—I had the hardest time picking people out based on my research, causing me to fret, etc. about something not coming out right. Now I figure I just gotta start somewhere, with tailors that seem well-respected and reputed by others. If I don't like what I get, I'll just move on.
Not saying I'll go on having $1k shirts made forever—like I said, if I get those first 6 shirts and they're less than expected, I'll go elsewhere.
How much more research? I've been reading absolutely everything I can about him and his product (and others, for comparison)—almost to an obsessive level (I can get a little obsessive )—since about May, and I won't be meeting him until the fall.