I was expecting the article to say how they've inherited a massive amount of money or how their parents paid for their education/first home/etc., which made them deciding to go frugal by achieving financial independence a hell of a lot easier. I didn't see any of that. Furthermore, the author doesn't fully explain how these two were "rich" before pursuing their journey to frugality aside from purchasing a home in Cam…
And a lucky one. I'm boggled that they found a 4 bedroom in Cambridge MA for $460k in 2012. I was very actively looking for real-estate in Cambridge that same year, and decent 3 bedroom condos started at $500k. I don't think I saw a single 4 bedroom single family home under $1M. Maybe it was a wreck that were able to fix up for not to much $$.
Today their formula can't be replicated here. Any place in that area that can rent for $4400/mo. costs well over $1M so they had great luck AND great timing (interest rates were around 3% also) - on top of smarts and hard work I'm sure.