A business needs to solve a real problem worth solving. If your product only appeals to a niche market, like knitted socks for kittens, it won't build a profitable business no matter how good the product is.
The second key question is all about the market. So what problem does the business solve? Is this problem worth solving? Is the product-market fit actually proven? Okay, now it's all well and good investing in a product, but if the product is all about, well, you know, it's some lady that knits socks for kittens, like, it's probably not a problem which is worth solving for the vast majority of people that's actually going to make a profitable business.
