This is not a joke, I'm genuinely curious whether "technical" cofounders are specific to the tech domain or if they are necessary in every startup (another example is chef / restaurants)
It depends on the category, really.
In this case, it's not as if Chobani invented the concept of strained yogurt. Rather, it practiced the time-honored art of geographical arbitrage: it found a product that had a long history of use overseas (Greek-style yogurt), and introduced it to the US in rather auspicious and on-trend times (the low-carb, high-protein craze). That's more a feat of marketing and operations than one of technical prowess or product development.
I'm sure that there were "yogurt experts" on hand to oversee production, ensure the right consistency, flavor, etc. But it doesn't appear as if there were a "yogurt expert" co-founder in this case. I might be wrong.
That's not to say that product wasn't crucial in this case, because it almost certainly was. But I don't think a "yogurt expert" co-founder would have been absolutely necessary, or that a "yogurt expert" presently occupies one of the top executive spots at Chobani the way a product person would at a tech firm.
"I came from a family of farmers who made cheese and yogurt..."
His dad was urging him to make cheese as early as 1998, and he did in fact start doing that a few years later.
I don't think many people decide to start selling yogurt because of a business opportunity. People that start yogurt companies are (hopefully) passionate about yogurt, and I would think they would have some experience in making their own yogurt. Starting a restaurant would be similar.
In summary, I think the main distinction is that the barrier of entry to programming (and engineering in general) is greater than that of making yogurt or cooking. There are many people passionate about computers and their applications that don't know anything about programming, but I would think there are far less people passionate about yogurt (and unhappy with the current offerings) that don't know anything about making yogurt.