This is quite right. These "bankers" won't be running hacker startups and the main reason is not their lack of technical ability but rather the "cultural" attitude in many of them that doing anything else (besides working in big finance) is a failure and a proof they are not that smart.
Of course, there is always room for a few exceptions.
Quants tend to be reasonably exposed, in terms of programming ability, and smart enough that they can pick up new languages quickly (necessary, as they're often used to crappy languages like C++).
Laid-off IBD/M&A analyst types are screwed, though, because they're pretty useless.
My brain is too full of internet memes; I keep on expecting to see a video of some banker huddling under a blanket and crying "leave Wall Street alone!"
A lot of people have been predicting a New York tech boom, following the collapse of the financial sector. Here's why I am skeptical:
1. Technology people and quants are the least likely to be laid off, because they are the most skilled. IBD/M&A kids will be cut loose, but they're useless from a startup perspective, since no one learns anything in the first 5 years of "soft skills" banking; it's grunt work too low-end to be educational from a business perspective, and the only coding involved is Excel/PowerPoint wizardry.
2. New York's biggest problem, from a startup perspective, is the high cost of housing, leading to a high burn rate. Housing will be "corrected" over time, but this will take years due to the lag, and a lot of tech talent will have bled out of New York in the interim.
New York will become stronger as a tech hub, but I'd bet on the Upper Midwest (Chicago, Ann Arbor, Madison, Minneapolis) before New York, since that area has both educated people and a low cost of living.