You can purchase your old benefit through FMLA for up to 36 months in an involuntary departure, but you pay 104% of the cost that previously was split between you and the employer.
In my case, my company "self-insures" but they hire processors (Bluecross, CIGNA, etc) to handle the claims. I doubt that any employer is processing all claims themselves directly. I would have to do the research, but it seems sensible to me that the processor would require some amount of money in escrow (or some other insurance policy) to cover such an event.
Most companies do and thus, most people believe they have a policy from the processor, not their company. Also many companies hire processors for payroll too (ADP and the likes). Does it seem sensible to you that in this case the payroll processor would require some amount of money in escrow to cover severance, PTO, California's WARN etc in case of bankruptcy?
I would assume that an actuary might put the cost of an unemployed person twice that than an employed person. Because technically people with chronic health problems would tend to be unemployed.