This type of thing could easily be negotiated early on in all the startups I’ve worked for. Even non dev employees.
Even worse for a remote job?
It sucks for anyone with health problems and sucks for anyone with children. People lose jobs because their children are sick and because they wind up with a major medical thing that happens. FMLA only covers large medical stuff - if you've worked full time for a year for a large enough company.
Some of this could be fixed with laws that protect employees and things like that. I'm generally thankful I don't have to deal with the lack of worker protection in the US right now - it meant that breaking my elbow while working a seasonal job didn't mean I was out of an income, for example.