I wouldn't assume I could start a restaurant or run a medical practice, why do so many people with no technical background assume that they can start a business centering around software?
History is littered with people who ignored your rule here and have been successful.
I guess we can flip that around: why do so many people with no business background assume that they can start a business?
If you want to start a company which makes software, actually knowing about software is going to do wonders for your chances of success.
As for your flipped question, “business” is not a background. Other than perhaps Math, English, and common sense, there is no knowledge that is so abstract that it can be usefully applied to any kind of business.
Unlike other people responding, I agree that people without a business background struggle when starting a business. There are a lot of developers who start a business and have no clue about pricing or marketing or sales.[0] They have a high failure rate.
If you know one side, you may succeed if you're a quick learner and/or your core idea is good enough, but you're at a disadvantage compared to an individual or team with knowledge of tech and business.
[0] Note that these are all things a developer could learn without a business degree, just like I learned to program without a CS degree.
[citation needed]
Do you have some examples? And do you have data supporting "lots"? Because I find that highly implausible.
Nowadays, though, there are dozens of different dynamics involved in the management of restaurants. As such, it is very difficult for someone who has both a culinary and business background to open a successful food shop. To believe that someone who does not possess such an expertise could do well in this arena is foolish.
Managing restaurants has always been difficult, but it is becoming harder with each passing year. Nobody in their right mind would recommend a complete amateur to open one of these shops given the current economy. They would need some sort of experience in the food industry before even attempting the feat.
[1] - https://en.wikipedia.org/wiki/FDA_Food_Safety_Modernization_...
Because starting a business, in and of itself, is trivial. Children do it with lemonade stands. It's "the thing that the business does" that is hard.
This is clearly a management failure. If you start a new department you should at least try to seed it with experienced employees from other parts of your company, even if they're on a loan.
Repeat this process several times until you have someone who will interview for you.
I think to some extent, it's a matter of being lucky picking the right person to vet, since you can't vet that person yourself.