The industry surrounding those markets (imagine bankers, financiers, lawyers, salespeople, corporate representatives and an entire swath of service people suppo

The industry surrounding those markets (imagine bankers, financiers, lawyers, salespeople, corporate representatives and an entire swath of service people supporting these guys) creates wealth and employment. Having top stock markets (and commodities markets) accelerates local economies and makes the city/country more important globally. See NYC, Tokyo, Hong Kong, Singapore, Shanghai and in fact even London. The more the listed companies you have, the more of all of the above jobs.