The high housing prices certianly lead to smaller homes/closet space, and the entire culture values quality over quantity, so it is understandable that Japanese men would appreciate and invest in fewer, but higher-quality clothing/shoes.
I do agree with your assessment of Tony's clientele. More guys than I would've expected show up at bespoke appointments wearing fairly standard outfits, including jeans.
Home ownership in Japan is a bit below the US and the UK, but higher than Germany. Their money clearly doesn't go to clothing. Or at least good clothing.