Well obviously if you are so sick that the only way for you to survive, financially and literally, is to have employer paid health insurance then ok don't take a sabbatical. This is of course a US-centric problem and would be absurd to basically anyone outside the US.

You don't even have to be "so sick"! for a family of 4 health insurance from a state exchange costs $1,000 a month and can come with a $7k per-person deductible. That's a minor car accident away from $26k in healthcare costs ($14k family deductible + $12k in annual premiums)...