I feel like describing him as a protagonist of book/movie misses that he was a real person.

I interpret that in the complete opposite way: he was a deeply unhappy person who didn't realize it until he really experienced being alone. I can be just as happy alone as when I'm with people so the sentiment certainly doesn't apply to some people

This is something many people overlook when they glorify this character

Let's pretend his passion was Nascar driving...