What it Takes to be a Private Banker in Asia?

WSJ has an interesting story on the booming private banking industry in Singapore.

Besides knowledge on financial products, to be a private banker one also has to learn how to choose correct attire (such as not to wear golden shoes) and use forks and knives in the appropriate manner. One also has to learn basic etiquette like don't ever touch the head of a Thai, don't wear black to a Chinese wedding, and eat before going to an Indian party so your hungry stomach doesn't gurgle while waiting for a late meal. It is actually quite interesting, read more here.

Another interesting bit is that the private banking industry in Asia is a far more labor-intensive mode of business than its counterpart in Europe. Whereas a private banker in Asia handles about 30 clients, an equivalent banker in Europe handles 10 times more at 300!

Any clue as to why that is the case?