Regarding Westy, you're right about the amount. I must have been thinking about another developer. Still $20k a month is big money, and his updates were pretty regular the last time I checked, though I admit that I haven't kept close tabs on him.
But you're still missing the point. It doesn't matter how many people are making more money with only occasional releases. It matters whether or not those same people would make more if they were releasing regularly. And "regularly" doesn't have to be monthly. It could be every second month, or maybe even every third month, provided that they're releasing on a regular basis and are keeping to their deadlines. Also, regular and transparent communication with the supporters factors into what I'm claiming.
Now I could be wrong in my entire contention here. That's possible, because we really don't have the data to either prove or disprove the theory. But the fact (If, indeed, it is a fact.) that there are more people who make money without releasing regular updates does not in any way disprove my claim that the same people would make more if they changed their development process/business practices.
Edit: To try to forestall anyone replying with "but these people are making more money", you cannot prove or disprove my point by comparing one developer's income with another's, or by comparing them with the group. You can only prove or disprove it by examining polling data from a large enough sampling of the total pool of supporters, or by examining data from developers who made changes in their communication and update cycles, and saw (or didn't see) changes in their support.