He left in 2013, most postdocs positions have a 5 year cutoff for eligibility. It's been 7 years since he got the degree so a lot of doors have already closed for postdoc opportunities. Professors will find reasons to not hire him such as being out of the game for too long and thus he's not caught up in the literature or whatever. He could try to go in as a data scientist. It is true though that usually that job goes to students because they're cheap and capable, they just take longer. So yeah it's kind of hard to compete against cheap, passionate labor that students provide.