I've done most of this. 10+ years ago I started working for a company in a city with good salaries (for Europe, not so much for the US), London. After a while I decided to go back to my home country, and the company offered me to work remotely. I've lived in my hometown for most of the past 9 years or so, a small town in southern Europe, much cheaper than London and any other big city, including the ones in my country.

Main differences vs. what the article says are: I've been working for the same company all these years, rather than chaining months-long contracts. Also (sadly?) I didn't invest most of my money, I simply saved it and bought a nice place this year almost upfront (had to get a mortgage for the taxes, basically). Also I've worked hard, very hard.

This strategy is good to make good money, I think. Often here in HN I see comments saying that you must hop from job to job in order to get raises, but if you stick long enough so that your knowledge is very valuable, the raises will keep coming.

Word of warning though: unless the company is remote-first you can forget about promotions, at least in my experience. It kinda hurts seeing how you've worked your ass off for a long time and despite making good money other people get promoted while you stick to the same role as when you joined.