"Execution" also includes selling the product and securing funding. A good non-technical co-founder handles all of this side of things so the technical guy can get on and write the code.

Without actual code you will fail after round 1. Even the best salesman can weasel for funding only for so long.

If the product is not innovative or much better than competitors, you will fail in a later round and best exit you can hope for is an acquihire.

This is why many startups fail, their ideas are meh and/or the execution does not follow.

I think it's more toward bad examples, which is most of the examples that I come across so I can see why you think that. But, this guy was good at sales, had an investor with money already in, had two customers sold on the platform, was already doing business in the space. He was a good example of a non-technical cofounder, he wasn't just saying he would do all the sales/marketing/finance like all non-technical co-founders always say they'll do, he was actually doing all of it already. His only problem was humility.

It seems you are assuming that execution is done mostly by technical co-founders. I would argue that many crucial aspects of what we categorise as "execution" are non-technical business aspects.

Are they now? What kind of aspects are you talking about?

Hiring? Ensuring funding? How long can those two last without a truly superior product?

In my opinion business factors like hiring and ensuring funding are way more important than having a superior product. Betamax was technically superior compared to VHS, Amiga OS was a better product than DOS, etc. etc.

Other non-technical factors, besides the ones you mentioned, are related to company culture, sales, HR and talent retention. Just a few examples that I can think of right now, there are many more of course.

While there are a ton of snake oil salesmen/women out there, there actually are people who are non-technical bringing other real skills to the table. Sometimes it's general business, sometimes sales, sometimes they really do have a deep domain understanding etc. So it's not always them looking to be the boss, but rather that they recognize a skills/knowledge gap and are trying to fill it.