At least here in the UK (I know slightly less so in the US, so your mileage may vary) it's extremely common for students who are either between high school / university or just graduated to take a 'gap year', or some other period of time to travel. For them price is clearly a very important factor, and the four months isn't a huge problem!
I think for most people, if they could afford 4 months off work then they wouldn't be too concerned about finding the cheapest possible flights.
It's still interesting in a theoretical way, but far less useful than the headline makes it sound.