Yeah, while this may be good advice for some types of markets/businesses/circumstances, there's no way that it's useful as general advice, especially not for side projects or small companies that only need to support one person. Getting that initial traction is the hardest part. Quitting after 3 months is silly.

I don't know how much Atlassian made in its first three months, but they are one of the only bootstrapped tech companies to go public in the last 2 decades. It took them 15 years. While this is not necessarily the fastest path to success, I 100% believe it deserves immense respect. They're one of the biggest success stories in tech as far as I'm concerned.

(Of note, Atlassian has mainly focused on enterprise markets)