An avenue that you may have not considered is Consulting.  With all of your years of experience and knowledge, you may fit nicely with a consulting firm that could use what you know to assist their clients. Or, if you realize your specialized experience or knowledge is marketable, Start your own Consulting LLC.  Very minimal startup cost and you already have the needed inventory in your head. Good Luck Guys!

I'm in the same boat (different financial picture). Have an MBA and used to be a CEO. Now it seems like I'm only qualified to sling packages for Amazon in the middle of the night. Didn't you know that once you turn 60 all your brains fall out?