Step 2. This piece of software becomes widely used, primarily since it's open source licensed
Step 3. (Modern variation) Person A feels cheated for not getting rich and creates some kind of drama.
This doesn't make any sense at all, to me.
Exactly. This and nothing else. I really don't understand why this is so hard to understand.
Of course it doesn't, because that's not what is explained. Read again maybe. If anything, the author asks for respect.
Your comment completely contradicts everything written in the article. It doesn't make sense to you because you don't want it to make sense to you.
Step 1. The author doesn't use GPL.
Step 2. The author clearly intended wiringPi to have a limited audience. He doesn't want it to become widely used. He intentionally limited support to a handful of hardware devices. It was meant to be used by experienced C programmers.
Step 3 isn't about the author being cheated. Fame or money were never mentioned. The author is overwhelmed with work, whether it is caused by the open source project, a new job or caring for his family doesn't matter.
However there is a special situation happening here that generally only applies to open software projects. The vast majority of the bug reports involve problems that have already been solved in newer versions. This means that even if the author had an infinite amount of time, all of it would be wasted on already solved problems. There is no reason to work on the project anymore since the rate of progress has stalled. The project has entered a zombie stage and then one day the maintainer announces that the project will be shutdown.