In fact, the wine Yan Fei is selling is making more money than Ma Chao's family ever did.
The Old Ma's family has been selling wine for so many years, and they're familiar with all the regular buyers in the surrounding area, so they're simply too embarrassed to charge too high. The price they quote is one thing, but in reality, they always give a little discount to whoever comes, or sometimes, they pour a bit more wine given the original price.
But Yan Fei has no qualms about selling expensive wine, especially since he knows fewer people. Plus, with Xu Xiaoyan up front, this girl is quite ruthless. Even when some locals come to buy wine, she doesn't even give them a discount. All the while, she'd have a big smile on her face and say, "Oh wow, Yan Fei just learned how to make wine! He's not very good at it yet, we're barely breaking even here!"