Many things can happen. Burn out, stress, hand cramps, eventual health declines etc.
Most webtoon authors basically have no life until they finish a season or go on hiatus
usually from overwork... some company pushes their author to meet deadlines so often
I mean, drawing like 100 panels a week can be pretty stressful, drawing can be exhausting, as an artist I sometimes get pain in my elbow for keeping it in the same position for hours, can't imagine how it is for them having a deadline
why is every manhwa author sick all the time? no hate just genuinely wondering