Well, as with everything, it really depends. But if you're going to do be launching a business by yourself, then hell yeah some business skills are going to be necessary. It is rarely the case that simply hacking together some web product will turn into a profitable business. In fact, if you take a look at a lot of the successes out there, I bet you'll find that the successful marketing and growth strategies were every bit as important as the actual offering, if not more.
1) It is really hard to be a sole startup founder. I would advise against being a sole founder. 100% of 0 = 0. startups have binary outcomes (most of the times).
2) A product really doesn't mean anything unless it's a 1 in a million amazing. Marketing and growth strategies as xwowsersx pointed out is extremely important (you will not succeed without great strategy) and I would imagine if you are a sole technical guy, you don't have time to think about coming up with marketing strategies because you'll be busy developing.
3) You have to realize people are smart and people have domain expertise in their respective fields. I'm a business guy. I'm pretty sure that I can pretty much take any hacker and come up with case study after case study of various marketing, managing, growth, hedging strategies that's worked/didn't work. That would save you hundreds of hours and thousands of dollars in opportunity cost. But that's my expertise. That's what I'm supposed to be good at. And even though in 12 months, I could probably learn coding, I would be at best middle 50 percentile (probably not even there). So instead of doing that, I would easily give up a huge chunk of equity to bring in someone who is an expert in coding and managing development. That's because all I care about is winning and maximizing my chances to ensure a successful outcome. And along the way, I'd learn various part of tech end and vice versa.
4) Some would argue that business skill is easy to acquire. I would highly doubt that. Unless you are an exceptional outlier, you can't be good at everything and you're brain isn't designed to. A backend specialist who is amazing at UI/UX design who is creative to come up with awesome marketing strategies and knows how to manage a team through the ups and downs? I haven't met anyone in real life yet that can do that. I'm sure some of these tech billionaires are, but that's why they're billionaires.
What kind of business do you want to start? I have some ideas too if you want to trade notes / work on it together. Don't worry about getting business experience before starting. Get a good team. Then you'll learn on the fly. And for some businesses, you may be able to start without a business guy. For most, you'll need one whether to create the deck, go raise funding, sell customers, execute strategy, get PR, schmooze for connections, etc etc. I can help out on the business end. Btw. ideas mean nothing. Execution is everything. And marketing/sales execution is a lot harder than novice entrepreneurs want to admit.