Without reading the article, $1M isn't nearly enough to retire on at 30, unless you have some disease that will kill you before you're 45.
In America, 35k per year was the 29th percentile for household income in 2014. An even more sustainable withdrawal rate of 30k per year puts you at the 24th percentile. [1]
Sure, you can't do it in San Francisco, but if you think you can't sustainably live on $1m, you're living in a bubble. Because a huge fraction of people in America essentially do it, but they also have to work forty or more hours a week.
[0]: https://gersteinfisher.com/wp-content/uploads/2018/04/Gerste...
[1]: https://en.wikipedia.org/wiki/Household_income_in_the_United...
It’s similarly the case that anyone who owns a home has to be prepared to drop non-trivial cash in a hurry for repairs. Combine a few things like that and you’re eating into principal.
It's true that if you've got the sort of job that lets you save $1m by the time you're 30, switching to a $40K/year lifestyle could feel like a bit of a step down. But, look on the bright side: you don't have to go to work.
You just need to ask yourself what you want from life, and choose accordingly.
That’s still 25 years of living if you get no interest or earnings.
Build a spreadsheet that has "expected return" (e.g., 1.06) and inflation (e.g., 1.03), annual expenses, taxes, starting principal, and then project out the annual rate of return net of expenses + taxes for 30-60 years from age 30. You will be surprised at how soon $1 million seems like nothing. Keep in mind that both expenses and returns can see shocks (not to mention taxes) that put you in a situation where "be below your earnings" assumption goes underwater and the compounding effects work against you rather than for you.
All I'm saying is this: be prepared that 5-20 years into your super-early retirement that you're kicked back into the job market--so have skills and a reasonable path for where you're going to come back into the market. It's not really a coincidence that many of these early retirement lifestyle gurus are supplementing their decisions via the job of competing for eyeballs as bloggers.
It's enough for some people to live on, not me though, I'd prefer to spend more.