I find that most people that program excel are most likely quants that just want to get the job done, do something to allow the bank to generate bigger profits.
Disclaimer: I work in one of these banks.
And if so, is the reason why no one has gone for the more bespoke route is because no one who programs is in charge of these companies, and thus does not even know that they could benefit from such an approach?
The only parallel I have some experience is in the publishing industry. No one thinks that the technical details of the CMS is important, as long as stories are visible on the Internet. But if a clunky CMS requires you to hire 10 to 20 people just to move pieces around on the frontpage (this is on top of the backend that automatically adds stories to the system and to their proper categories), then that is not a trivial cost.
And I'm sure The Verge, with its custom CMS (in Rails, it seems) has some clunkiness to deal with, but they've been able to produce varied and interesting formats for their stories on a much more everyday basis than even the New York Times (I'm not counting interactive graphics/multimedia, I mean the general story form).
Where are they getting all this talent from? I assume they need atleast a certain degree of expertise which is incredibly difficult to get out of people right now...
Turns out, it isn't a perfect description of reality.
Engineered lumber is when you glue a bunch of different woods together. The resulting product has different properties from any of the original woods. It is more profitable for the lumber company because it can be sold at a price premium.
Similarly, financial engineering involves packaging up multiple financial products into a more complicated product. The product can then be sold at a higher price to gullible fools, aka "customers."