Passive is the opposite of active, I get the definition. Something you're no longer really actively working on that keeps making money. I'm jealous, I'd love to have such an idea.
But this seems different -so far-. This is more akin to building 80 money printing machines that each print a certain amount of money. They may work forever, or die in 6 months, or not work at all.
I guess my entire point is that this is a monumental amount of seemingly continuing effort. It's simply too early to call it passive IMO.
However, dates are missing here. If OP wrote his last book 5 years ago and is collecting this income each year, I'll gladly eat crow.