I am an ex-engineer working in a bank as some calls it front office treasury role.

As for the question on why engineers are lowly paid compared to bankers, it all boils down how much money can you bring to the firm.

E.g. I used to work as R&D engineer, and I work together wih 10+ R&D engineers to innovate 1 product, and a assembly line with another set of product engineers, technicans and factory workers to produce the finished product. Besides of the huge human resources requirements, there are large capital expenditures e.g. machines, factories. The margin is low with high overheads (engineer pay is one major overhead).

In a bank on financial markets, there is product developement team called the quants, abt 3-4 people with phd in maths, who comes up with new structured products and risk management solutions, a desk of 3 traders who manage the risks, a few sales to push the product. There is a middle/back office settling the trades, etc. For a relative small operations, the pnl can be enormous at roughly 5% of volume, thus can be around USD25mio/yr. Divide the bounty between 5-10 FO staff, and you can see how much bonus they get.