Is the company that much more likely to blow up and go out of business due to inexperience of the younger guys at the helm? Perhaps, but it's their company and that's how you gain experience in the first place. And IF it blows up in their face they'll learn (hopefully) and their 2nd, 3rd, 4th shots will be so much better.
50yo+ just need to stay away from these places to avoid becoming collateral damage. We don't have our entire lives ahead of us to make up for the lost time and wages. So not getting hired there is not really a problem.
Of course it leaves 50yo+ with fewer places to work and earn salary. Sucks, believe me, I know.