I have been doing coding for some years now. Went from terrible to average and sometimes even good. Still no passion. And I'll never be one of the really good devs, my learning speed during work isn't high enough. I know what to do to get better, how to practice. But that would require huge time investments during my after work hours.

And for what? Doing more of the same I don't really like, so that my employers profit even more of my work? I can't convince myself to spend time that way and don't believe I could do it for more than a couple of weeks before burning out. So, maybe you start liking what you do if you become really good at it. But there is an assumption, that anyone can become really good at what they are doing. Or if I remember that book correctly, that case was covered by noticing that everyone else is going to drop out of the profession. In any case, not everyone drops out of the profession who isn't good at it and not everyone who stays inside the profession will become good eventually. But sure, whose who are really good will properly enjoy it.