I disagree that nothing one could have done beforehand could fix that. The argument is not that there would not be a decline in share prices at all but the magnitude of it.

You need to have enough saved to survive 6 months w/o income is preached a lot in personal finance and somehow this is not practiced for businesses.It is understandable that cash-strapped startups can't afford to do this but the companies buying back shares to increase their stock price certainly could.