There is huge demand for special clothing and believe it or not Suit today is a special clothing. The point is really people's idea of dressing has changed. There were times when costly clothing automatically meant something. Those days are gone. I find it difficult to imagine, people wearing suits to work these days. Most of them look like 'Odd ones out'.

I don't like to wear a suit, nor does anybody around me unless they are getting married or they are about to meet somebody powerful and rich. There fore clothing industry is 'optimized for the common case'. The only clothing I find worth buying these days is rugged jeans and polo T-shirts. Anything else and I find that to be focusing on ornament more than the substance. Therefore the demand and supply moves in that direction.

The place for bespoke suits today is the distinction that tailored clothing carries. So they continue to remain clothing for 'special occasions'. Needless to say if you want to maintain that sort of distinction, you can't use machines to scale. Because that would mean you that sort of clothing no longer carries that distinction.

Its not that these artists/tailors can't make money other way. They can probably get a job else where and live in better conditions- if they want to. But sometimes people stick to what they do and how they do for unexplainable reasons.