” There is a HUGE glut of unwanted older STEM related professionals that have been essentially cast aside after 15-20 years of experience.”
No. I am 61 years old and I still get contacted by headhunters. You just have to stay current. Project Managers are a dime a dozen. They want coders. Programming in PL/1 in the 1980’s isn’t “current”. They want Java, SQL, even COBOL. 98% of my job is head-down coding.
That is nice for coders...the other 90% of STEM folks are SOL.