I readily agree these selection processes are not perfect, and institutional nepotism in particular is an issue in academia.
You can get a coding job just by acing a coding interview (and having basic social/professional skills). So this part of your comment did appear to suggest that merely publishing papers can be sufficient to obtain an academic position.
What possible reason would I have to interview someone if they had neither relevant experience, nor a degree? Should I just ask random people I see on the street to come in for an interview?
If you're talking about people who have no experience in the sense that they've never written a line of code, then no, obviously not. But professional experience and relevant qualifications are not necessary.
As with any job application, you need to have something going for you. It just doesn't have to be any of those two things.
I don't understand your rhetorical questions. Clearly, yes, conferences choose bad speakers sometimes.