Back in 2013, as part of my consultancy services, I built a simple email support site for a client, whose most difficult part was just a background job (mailman) that would need to pull emails from different providers and send emails through them, as per replied by this client's support reps. The customer wanted a sort of custom service rather than using Zendesk or something, because he was providing a "outsourced support services" to his clients. I charged only $950 to build the initial version, but charged monthly maintenance which started from $300 something, and over the months/years went onto $840+ monthly.
Mostly, it was Mailman that would require some tweaks re error handling/retry logic, as there were weird errors I would see from different providers once in a while. However, the code would work flawlessly and for months I didn't even need to check it at all.
So, yes it's possible IMO, just that you need to be in a right situation at the right time with the mindset of a hacker (the one who wants to make machine works for him), you can achieve something like this.