If you're building e-trade that's tangible, but the majority of engineers in finance are building internal tools to assist in finding arbitrage opportunities for the firms they work for.

I don't think you realize how complex the software in the financial industry is. Finance is probably the second most software driven industry in the world after the software industry itself.

Only a tiny percentage of developers in the financial world are working on arbitrage, the average bank probably has more developers working on compliance software than arbitrage software. A vast majority of software development work at most banks is infrastructure (integration between systems, data feeds, settlement, etc.) which supports the day-to-day operations.

You're right, I'm painting with too wide a brush. My main problem is with investment banks who make the profits while the taxpayers take the risk. It really has nothing to do with tangible or not.