I think the advice is intended for products you build for users, not products you build for clients. The right strategy depends on who your customer is. When you find a ripe market, you'll discover that your customers—i.e., the users—just want a solution, even if it isn't pretty. When your customer is the client, then you're selling to him, not to his users, which means you rationally should care less about the product. This can be painful, which is one reason why many startup founders prefer to avoid client work.