Matt,
I worked 3 years on money market trading systems at a large bank, which included a course of training on the banking industry. Not exactly an MBA, but it's more than just working on code without any clue about what's going on in the underlying business. I've also worked on other trading-type software, and worked in the investment bank environment, allowing
a certain amount of osmotic learning.
But the fact of the matter is, knowledge of the business is not enough. If you don't have the specific technical skills and experience they want, they won't be interested. (There may be exceptions for the top 0.5% MIT grads. Most people don't fit that description.)
I'd actually bet that someone with specific technical experience, but no business experience, would most often get hired rather than someone with business experience and less technical experience.
This is because an organization will have lots of people around with business knowledge, from whom you can pick things up. Some large organizations, like the bank I worked for, will have an established training program to teach new employees about the business. But with technical skill, there are fewer people from whom you could learn on the job, and formal training programs are less common, because the skills are too specialized. (A course about banking would be useful for employees in many departments. A course about SQL would be useful for a much smaller group of employees, so it's better to just hire people with that skill.)
It's easier to grab someone and ask them to explain Eurodollar interest rates over lunch, than it is to get a coworker to teach you C++ or Struts.
Generally, in job ads, experience in the field of business is listed as "a plus", not a requirement.