Humble Bundle is basically a publisher with a web storefront. They leverage other distribution channels, and critically, have what's left of the gaming press as a very fruitful marketing channel.
They also mostly only publish things that are already hits, so in a lot of ways they are a re-user outlet.
Other storefronts... That would be nice if people could make money on those other distribution channels. Unfortunately, they can't, by and large. Most people don't find the effort worth it to even sign up with Amazon, which has a huge addressable market. I have never even seen a sales report with money from fdroid. For devs who are trying to make a living just from games, anything other than Steam, iOS, and for some people, Google Play, is basically irrelevant. Unless you land in a Humble Bundle.
As far as the loyal audience, yes, I agree with you on that, even mentioned it in the article. But that's not a living wage for most, and the latest research says that sort of environment is more susceptible to a hit-driven winner-takes-all market. That leads to an ugly place as regards the income levels for the typical dev.
You're misreading the issue. The issue is whether anyone can make money other than the few oligarchs who got in early. Whether anyone can make money unless they are pandering to the lowest common denominator for the sake of mere profitability. Whether even the top quality titles can make money given the need to spend at insane rates in order to be visible.
It's absolutely true you can do it for the love of it. Not questioning that. But the above is a recipe for a crash.
They also mostly only publish things that are already hits, so in a lot of ways they are a re-user outlet.