Yes, I think we can sum it up as "Never meet your heroes". We tend to build an inaccurate image of those we look up to personally and the culture also builds a kind of communal shared false image for (probably all) popular figures like writers.

Sitting in front of a computer all day long isn't healthy either.

Definitely not. That said, sitting in front of a typewriter was probably the healthiest thing some of these people did.

Writing is an isolating profession, and its demons compound when you introduce other vices.