Have you ever had the perception passive investments in general (stocks, real estate funds...) generate a very low profit margin?
It stays around 0,6% monthly profit, what means you need 100,000$ invested in order to generate 600$ bucks a month.
For the average investor who is saving pennies or few hundreds of dollars every month on the best scenario, it will take a long time until he reaches somewhere in this financial world.
Therefore, for those who are starting their financial journey just now, maybe it's more advisable to allocate their funds on non-passive investments, what means they won't have a source of automatic profit, but at least they can pursue superior returns to maximize the potential of their money to generate further monthly income.
Once they manage doing this first step, then passive income investments start looking more attractive.
If you are a practical person and you have an idea about cryptocurrency or Bitcoin, it is better to just put your funds in bitcoin because you know that the chances are high that the return on bitcoin will be really good.
This has been proven, now it is also okay for real estate and others, it just depends on what others discover in which they think there is really potential, that's all.