It is mentioned that as you do this, you stay alert and work to decrease expenses...
Freeing up headspace while having that "cushion" so one can begin to turn in the direction of finding fulfilling and enjoyable income sources. Easy enough to re-evaluate and change or tweak each year.
After you get your 2 years worth saved up, if I'm understanding correctly, during that first year that you "live off of half your savings", you are actively working toward finding where the 2 extremes meet (your reduced expenses compared to your actual income. Maybe after that first year you decide you need to work toward a higher income- you will have a year, now, to correct that discrepancy! (At least a year, because he's not advocating sitting on your butt and doing nothing during that year).
At that point you will still be ahead of the game- plenty of time to correct course (or turn tail and abort entirely, lol, if you so decide) and you will have learned a ton without risking total financial ruin or feeling defeated before you even start. And you will have so much more information that can definitely work in your favor as you age. When it comes to finding work that gives you purpose and joy- and that you can do for as long as you choose- yeah, this is an attractive workable blueprint alternative to the "Save a million" advice that's out there now...