The Engineer builds a clever device, which costs 20 bucks to build. What is it worth if nobody buys it? It is worth nothing. This is the starting point.
The Salesman appears and finds the customers and sells for the highest possible price.
A good salesman will sell the product for more money than initially expected, let's say 100 bucks.
Finally, what if he sells 100.000 units?
Who deserves more money? The Engineer or the Salesman? What was the feat of the Engineer? Building a 20 bucks device? If you have customers to sell 100.000 units at 100 bucks of a device that costs 20 bucks to produce, it will be easy to find an Engineer to build it.
Same with "Financial Engineer". Look at their wages in percentage of the gross profit their work generates. That's all there is.
So the conclusion is: if I find a customer who want to buy 1.000.000 kitchen heat pads for 10 US$/piece, hell, I would be able to supply him! I would be the master expert in kitchen heat pads in days and find who could produce them for 1 US$/piece. The hard part is not to develop/produce a product, it is to find who will purchase it. You don't believe me? How can Apple sell their iPhones for such high prices, if you get higher spec phones for a fraction? It is because the marketing guys know how to sell!
If you really want to make money, skip any technical job. It is in sales and finance where you can make real money. Also, while we engineers tend to look down at sales and finance people, thinking we are much smarter, the truth is, that the successfull ones are brilliant in what they do.
And remember - Being rich is not all about money, but how well you spend your precious time!
Cheers,
Vitor