Isn't it very rational and reasonable to have a system that ties health care to employment when a health crisis can cause mass unemployment?

Bingo! You're very astute in pointing out one of worst flaws in our health care system. Until we have guaranteed HC coverage for *all citizens (ie; nobody "falls thru the cracks") it's a system that fails everyone. This pandemic has underscored that point perfectly.

It's been long established that access to healthcare for most Americans only being had if they have an employer who provides it as a fringe benefit is a poor system, especially as fewer and fewer employers offered health insurance benefits, often convoluting their employment methods in order to avoid it as healthcare costs and so health insurance premiums skyrocket and have been skyrocketing non-stop since the late 1980s.  

This pandemic, though, has definitely further underscored that fact.

From the perspective of insurance companies - yes

For private citizens - no

I have not read anything yet about how the health insurance industry is being affected by the coronavirus up to this point in time.

No. health care is free enterprise. If you want it, you pay for it with insurance, with cash or with others' tax dollars.

Thank FDR. Thanks to his wage controls, businesses started offering benefits to get around them. That's how we got healthcare tied to jobs.

If you can't afford to get sick when you don't have a job, just stop being poor, it's not rocket surgery.