The fact that the apps were incredibly well-made didn't hurt.
And this underscores the whole point - success is a probability function, it is hardly ever guaranteed. The author seems to blow this out of proportion though, and suggests the common refrain that one should just give up/get out of the game. This ignores the innumerable things you can do to improve your own odds, that others aren't doing already.
A large part of that is to make sure that your product/skill is actually good. But that is incomplete.
Without giving away the secret sauce, does that company have a strong niche that they excel in? I am fascinated by competent marketing; one of the apps I mentioned, before their launch, basically pulled together anyone who had ever emailed them about their previous apps and sent a really gorgeous teaser email.
I also wonder if your app icons are in the top 1%.
It is luck. If you emphasize the preparation part (of 'where preparation meets opportunity' -Seneca).
Of the three developers I know who have been featured in the App Store (New & Noteworthy, not the main spotlight), Apple contacted them out of the blue. In one case, they asked one of them to change their App title so it was less spammy (it was). All of the apps were polished and worthy of the designation (and not games). We believe that App Store reviewers have a special queue to submit noteworthy apps that are then editorially reviewed. Really, as an upstream commenter noted about reviewing film festival submissions, there is a lot of mediocre apps - good ones stand out in the stream.