Lots of worthwhile observations in the article, but I think the framing is a bit off. It sounds transactional and by the numbers.

I think it's fairly well understood that vocal users aren't necessarily representative. The bulk of your happy users will never contact you for support. But they are some of the most important users to talk to to improve the product.

You need to build your own model of who your users are to provide a basis for interpreting user requests: is the support request signal or noise? if the request is coming from someone in your target market, and expressing a pain point, that's potentially an important signal. If the request is to charge only 20% of your current price, that's only useful if you're prepared to consider restructuring your offering (receiving many such emails might signal an opportunity for a budget product with specific feature subset) -- otherwise: "Thanks for your email, we don't have any plans to change our price right now." move on.

By the way, I'm impressed that this is even a conversation for a developer selling through the App Store. I always felt that Apple killed the ability to maintain customer relationships by injecting themselves into the process. Never published on the Mac App store myself.