How are you still breathing after 32 years? You've been experiencing your story for so long, so how are you doing it?!
It sounds like you haven't found a burning passion or hobby. "Time" dissipates when you're balls deep into an aspect that you love endlessly and can't get enough of.
Youe life story changes much more than the story of a manga, in tje same amount of time. Look at how much a manga actually progresses. Like one arc of One Piece will take a couple years to write in some cases. Characters haven't seen each other for 40 episodes, which will take a few weeks to watch, but IRL it can be a whole year for the mangaka.
You're also comparing survival (staying alive) to a non-vital endeavour.
You think incorrectly that an intense passion must inevitably last for a very long time. That if it didn't last for 15 years say, that it therefore was not intense. By your logic, intense relationships that burn out after a few months or a couple years wouldn't exist. I've had intense passions, but it is still unusual for someone to sustain focus on something for so long.
These mangaka go through 10-20 years of writing and in that time they pass through various life stages. They have children, maybe lose some family, go from being very young to middle-aged or develop health issues. These are things that can and often do change priorities in life or the amount of time and energy people have to do something. Even the fact they manage to stay with one publisher/magazine for so long is unusual, considering how rare it is to have one employer for so long. So you're also ignoring that sustaining one endeavour for so long is about more than just passion, but also about those sort of outside factors.
I also doubt you've got something you've been working on for 15 years like a mangaka has. Like "self-improvement" wouldn't count, because it's not such a narrow focus like writing one story (it's more like writing a bunch of short stories or novels).
