It's not so much that they're paying for a C++ developer, they're paying for a C++ developer (or C#/Java/whatever developer) with a certain set of skills. The

It's not so much that they're paying for a C++ developer, they're paying for a C++ developer (or C#/Java/whatever developer) with a certain set of skills. The sort of developers that get well paid in finance (it should be noted that there's a vast range of dev salaries in banking depending on the sort of roles being worked in with Quants, Quant/Devs and Front Office developers being very much at the top of the pile) are those that have Masters or PhDs in Maths and work on pricing algorithms, those who work on high frequency type applications, those who have enough maths that they can turn algorithms into solid applications that can't fall over during the trading day (i.e. solid, highly optimised software), or those who can interact with the trading desks and build anything which helps the desk make more money. One thing they'll all have in common as well is a large amount of domain knowledge about the (financial) products that they work on, as well as the ability to work in environment which are often noisy and stressful. Anyone who needs their own office and a quiet environment in order to get into the zone and hack on some code is not going to thrive at a bank.