You can find plenty of people who will argue vehemently that it isn't legalized gambling on top of a pyramid scheme. One that can collapse faster than you can say "bank run".

We were talking about banks 'making money' by giving out loans the other day. The banks actually have collateral and the fractional reserve. The only 'money' in the stock market is during active trading. Every penny of it leaves after the last trade is settled. At night the Dow is only worth the liquidation value of the companies (and that's if there are only common shares, otherwise forget it), and that's a smaller fraction than either the collateral or the fractional reserve banks maintain. Let alone both together.