For the first decade of my career, I really believed this, and spent a lot of time doing split tests, and studying analytics, and trying to "make things better" by understanding the numbers as they were given to me.
This was a mistake.
I've since learned that these numbers will rarely help me make meaningful improvements to my product, and my business. Sure, they can be useful so that I'm not "running blind," but they simply aren't going to show me how to create an ingenious idea that takes things to the next level.
Analytics will help you optimize things to a "local maximum", but they'll blind you to the real possibilities of creating something new that can completely transform a business. As soon as I understood this distinction, I've been quite a lot more effective.
There's a similar problem with things like "user interviews." A common pitfall is to ask people which features they want. That has limited use. The real work you need to do is the "creative thinking" that others haven't done. Figure out what people don't know they want; learn what the numbers can't tell you. Then go and build it. Yes, understand the numbers, choose a good business model, and optimize based on those numbers, but don't let the numbers create the product. It's a dead end.