I am pretty sure that my Github profile had absolutely no effect on any of the hire/no-hire decisions I was subject to, or even on whether I was entered into a

I am pretty sure that my Github profile had absolutely no effect on any of the hire/no-hire decisions I was subject to, or even on whether I was entered into a company's interview pipeline. A couple of work projects from my previous employer were hosted there and accessible from my profile, so my profile wasn't barren. I highly suspect your ability to summarize your 20 years experience well in a 1 page document will matter a lot more. And you don't need a project to be on Github to be able to talk about it in interview.