Facebook very probably has a group long-term disability insurance policy which adequately its employees in that case. Google did when I worked there many years ago. Some supports might also come from Social Security Disability Insurance, Medicare, and loans or withdrawals from retirement accounts that are far better funded at Facebook US than at Facebook UK.
It eventually runs out, yes, but the good long-term disability policies last until retirement age, when social security retirement benefits kick in. You may be confusing it with a short-term disability policy, which is more common, or with mediocre long-term policies.
Medical bankruptcy is indeed pretty widespread in the US, but not among people with Facebook or Google benefits, not even those with career-ending disabilities. You’re underestimating the inequality of benefits within the US.
Not a permanent work stoppage example, but here is one relevant anecdote: I have personal knowledge of someone who got severely crippled by a freak accident that would have made most Americans go bankrupt and never be able to work again, including a need for repeated brain surgery. His FAANG employer benefits paid for what he needed, and although he was permanently wheelchair bound, he was eventually even able to return to work part-time (of course not initially) because of how good their benefits are.
I don’t have statistical data, but I have worked at one of those companies in the past and am familiar with the caliber of compensation and benefits, so I’m generalizing from firsthand knowledge.
Honestly, even the comp allows building savings so rapidly that it helps a lot even before considering the benefits - and one of the benefits, at least at Google, was by far the best 401(k) plan I’ve ever heard of, including allowing less common options in the law which most plans don’t want the administrative hassle of allowing, and lower expenses than retail investing. So personal wealth (and therefore defense against high medical bills) grows really fast at those companies, and then the benefits most allow the employees not to spend those savings on medical costs.
Dismiss my assertions if you like, since they indeed aren’t statistically proved. But I don’t think there’s likely to exist public statistical data either proving or disproving my claim, so assertions like mine are the best we have. Any private data that might exist with sufficiently tailored scope would be kept within the HR department of Facebook or Google, and I’ve never seen it.
I should also probably clarify that I’m talking about US technical or managerial/executive full-time employees and not, say, someone who works in a warehouse shipping Google Store phone purchases, or employees with a foreign comp and benefits package.