It matters a great deal if a division fails precisely because most companies only have one of them. If the company had two, certainly one could fail - but often companies don't have the resources for two. Splitting the division into two equal parts often isn't practical - sometimes it takes five people to complete a job and the company only has money for five salaries. And for most functional divisions - human resources, marketing, product management, finance, etc. - I really don't understand how the company could have two parallel organizations operating simultaneously, even if they had the resources, without causing damage to and confusion in the company.
I get that you'd like things to work differently - but I can only tell you how they work currently, at every company I've ever been a part of. If you can persuade a company to hire you as the vice president of something without lengthy experience, that's terrific, and I wish you much success. But you asked why companies don't generally do this, and I've told you.
Yes, some companies really do split the functional divisions of HR, marketing, product management, finance, etc. They are rare but they are quite successful otherwise I wouldn't be asking this question to figure out why more companies don't do the same?
Why does it matter if a division fails? It's only one part of many as if you have many divisions doing the same thing trying competing for the same prize, with the winning division getting it, what's wrong with that? Isn't that how Apple made it to the top?
I don't get this argument. Why not just split the division or create two and have them fight it out to create the better product? Kind of like the Mac, Lisa, and Apple II team worked?