Talk to friends who work in non-Tech industries, ask them their most time intensive/monotonous task. It can be industry/domain specific or not. If they can’t think of any specific, ask people lower down the food chain, e.g. interns, new joiners, etc. They will be probably given a lot of boring grunt work then see if someone would pay for it and if you can automate it.

The author of the article was working within a call center and got to see how it could be disrupted, price.

Not a perfect formula, but you can start to see areas that need improvement. Also make sure companies are willing to pay for it.