Many startups fail because they're actually not innovative. Nobody needs another database from a tiny company that is just tiny bit better. No matter how good rest of your offering is, bigger does often mean better.
Other fail due to entanglements, especially hardware ones. Their supply chain fails and that's that. No amount of media will help and you cannot afford to hedge this kind of risk.
If you're already bringing the technical skills, you probably want to partner with someone that has the skills you lack. In particular you'd probably want business development skills, but you'd also want them to be able to jump in and get involved with designs/mockups so you can focus on the technical side.
As an aside, maybe I just don't 'get it' or maybe I've just met bad examples but this scenario always reads to me like "guy wants someone to do the work for him so he can be the boss".
Good ideas are cheap. Execution is the hard bit.
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.
Hiring? Ensuring funding? How long can those two last without a truly superior product?
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.
In the end, the system that a company is built from will be complex.
Execution is about knowing which parts of the system should be complex and which parts should be simple.
But, from our two hour meeting I could tell that he wanted to make all of those same mistakes I now know not to make.
Your point about building complex shit is exactly his main problem, and I problem I suffered from at that age too. Yes, it might be complex one day if that's what the market needs, but simple can be so much more and it's especially the right move for an MVP.
To some degree, I don't blame him and he doesn't know me well enough to trust me to guide him away from those pitfalls, but man I wish he had a little more humility -- we'd be a couple months away from an MVP at this point.