@thewordgirl I have some experience running teams as a C level and also working with various stakeholders so let me give you my perspective. I am sure some will disagree because my view is the opposite to what you have described.
"I don't know" is the right answer. A CTO does not have access to skills and information that nobody else has access to. They simply have experience. And through experience they probably know that every company is different. So what works for their previous company might not work at all for their new role. It really takes time to be an effective C-level. I think that on average it should take 1-3 months during which you should aim not to make any major changes which I believe could risk sending the company on the wrong track. One of the main jobs of the C-level is to come up with 2-3 important goals and drill them into people's heads. You need to do other things too but this is very important. These 2-3 items could really make a difference. So the CTO is more of a curator with good taste and awareness of market trends.
As to your question, how do you hire technical people if you are not technical, well, it is the same as trying to pick the best quality wine without knowing anything about wine. You can use multiple factors, rules of the thumb, to make an educated guess. You can look at who made it, the price, the presentation, etc and those could be good properties that help the selection. If the wine is really expensive you should consult with an expert that will help you make the best choice