Well so far extracting money from dumb customers is still an excellent business to be in. eg charging $47m for a spreadsheet with a $100m error [1] or helping Libya invest its money in trades that soon became worthless[2]. It is hard to make money like that from trading alone with such low risk.

But Goldman can see the writing on the wall, and now has 25% of its staff in tech, because the markets are changing fast. Stupid people will still make up much of the revenue stream for a long time though, and large companies that like to pay large sums.

[1] http://blogs.wsj.com/moneybeat/2014/10/16/spreadsheet-mistak...

[2] http://www.theguardian.com/business/2014/oct/06/goldman-sach...