I think the entrepreneurial route is the most realistic route in the long term. The idea is to use your experience and knowledge to build a software product that a niche market needs, and sell it.

If you live outside the main city centers like Silicon Valley, New York, Los Angeles etc. its not hard to make a full-time income online.

A key thing to understand is that, as an employee working for someone else, your revenue will always be capped to the rate associated to the job market of that profession. There might be a 10% difference between jobs, but that's it.

While if working as an entrepreneur, your revenue cap is the one of the market you are on, whatever that is.