Again, I think you're mischaracterising me a little bit.
I can't code. I'm not a technical co-founder. My first business was not a software business, it was an IT infrastructure business.
In my first business, I discovered a need in the Japanese market for a good invoicing/document management software. It came about through me building a crappy invoice management system, and showing it to other Japanese business owners.
It was a little scary to work seriously on this, since there were no competitors, hence possibly no market.
However, I went out and did the following:
a) Designed and had built a crappy version of the software that was functional, but not elegant or scalable.
b) Talked with nearly a hundred potential users of this software to find out how they're currently solving this problem, and to try to get a sense of the market and the potential demand.
c) Found a group of people who were very interested in buying this software.
So by the time I found my co-founder, I had already invested hundreds of hours, and tens of thousands of dollars. However, I had a working prototype, many potential customers, and a good feel of the market.
It was a LOT of work. When people dismiss business co-founders as not doing a lot of work, or not doing meaningful work, it's both very irritating and also leads me to believe they've never worked with a 'real' business co-founder.