How did your friends go about finding non-programmer markets? I can't leave my current role in tech because I don't have a big safety net, but I want to understand other markets and figure out inefficiencies. I've seen this advice about exploring non-tech industries pop up a lot and am interested in following through.
Easiest: Find a random industry. You'll see job openings for programmers. You'll probably be wildly overqualified. Get a job there. Make sure it's a job where you can keep your head up and learn to industry (and not be isolated in a cubicle).
Harder: Nerd out on something not computer science. Take classes in oddball topics. Go to industry conferences. Network and hang out in online forums.
I once hopped on a plane and went to a conference in a 90% unrelated industry that I had taken an interest in. Even gave a workshop there -- as an outsider looking in, around a relevant idea. Expensive, but I learned a ton and came out with a powerful network.