I really hate your title, because it's misleading, even relative to the article contents, which I actually liked!

Passive income is neither a lie nor a myth (see, e.g., https://medium.com/financial-strategy/no-myth-you-absolutely-can-create-passive-income-db99c7e3d3e).

However, as you correctly point out, it can't (reliably) be done overnight. There are ways you can become wealthy overnight with zero effort, but those are beyond our control (e.g., win a huge lottery jackpot or have someone leave you a fortune).

For things we can control, true passive income requires a lot of upfront investment of time and effort.

It could be in buying rental properties or shares of stocks or mutual funds, both of which require you to spend time and effort to come up with the initial capital, learning how to pick the right investments, and making those investments.

Most things people call passive are actually not - e.g., blogging (Medium or elsewhere) requires you to keep churning out valuable content or people forget you and your income dries up.