This reply is somewhat disingenuous. Read the question instead as "can your average millennial stuff away 64% of their income?"

To achieve the "shockingly simple" 11 year FIRE goal in that blog post, someone working 40 hour weeks at $15 an hour would need to indefinitely keep their annual expenses below an inflation-adjusted $12K to build the required savings prior to their early retirement and to live off those savings afterwards.

In reality, the math is only shockingly simple if you can control all the inputs.