You overstate your case quite a bit. There are a lot of products for which great visual design or very-well tuned usability are, frankly, not necessary for market success. Consider, for example, this very site. Some startups do indeed need great design, though.
Even for those startups where design is crucial, I think I'd only go as far as saying that the founding team needs someone with a strong design sense and some specific design skill. But that person needs to be a lot more than a designer.
Consider Chad Hurley, for example. YouTube beat out many competitors partly because of a much more usable design. But Hurley was also CEO and head of product, and he handed off the details of design early on to others. Even years later he still reviewed all the new features before they went live, but that's much more about his ability to evaluate design (and design's impact on metrics, which YouTube used heavily) than it is about being a designer.
Design evaluation and quantitative analysis based on analytics are part of what designers do to validate design decisions (identifying bottlenecks in task-driven applications, optimizing Ui and user flows to increase conversion rates, etc). These techniques are part of a beta or post-launch iterative design process.
Your point about Hurley having entrepreneurial skills above his particular profession applies to technical founders as well (or any founder for that matter), not just designers. Unless you think that just by having the skills to do programming at early stages of a startup can alone make for a good founder in the long run.
Even for products that don't have an UI at all there are many aspects of the customer experience that will require conscious design efforts to give you a competitive edge. A designer perspective can bring creative and fresh solutions to many types of business challenges due to overlaps with Marketing and business strategy. Integrating behavioral economics principles to your business through design can have a huge impact on marketing and sales regardless of what your product or service is about.
Design DOES mean business, and the fact that it is recognized more every day is a prove of that. I would have Ives as my cofounder and not just because he can design great products, but because he can design a great company. He also has an amazing networking, I bet.
This myope perspective about design is probably the main reason why companies and startups can't get experienced designers to join.
I believe everybody at a startup should think and care a lot about design, so I think we mostly agree.
I would like "designer" to mean what you say it means, but I think a relatively small fraction of people who identify as designers can actually do what you describe.
My point about Hurley wasn't that he had entrepreneurial skills on top of design skills. My point was that even for a billion-dollar success for which usability was a major success factor, it wasn't his visual design skills that made the difference: it was that he valued usability and had the ability to evaluate usability impacts. It is true that some designers have that, but one does not have to be a designer to have those skills.
I think you are right, we mostly agree on this. It is just the way you refer to visual design and usability evaluation what was confusing me. They both come with the design endeavor, but being able to evaluate its impact and to execute based on this is not exclusive to designers. Thanks for the clarification.
This is where I think design is misunderstood. The minimalist design of this site is likely a huge component of keeping the debate at the level that it is. In my book, that is great design - not creating an eye pleasing knockoff of a 37Signals landing page.
I'm not sure I'd agree the design is great, especially along the axes I mentioned, but it's certainly solid, and adequate for the purpose and audience. Either way, though, I think we agree that one does not need to have Jonathan Ive as a co-founder to build something like this, which was my main point.
