Scalable income usually starts small but pays off in the long term.
You could spend your day, say 8 hours writing an article for Medium. You may end up earning $5 from that article in the beginning.
You could have instead does some consulting or coaching for $50 an hour and made $400.
But you can only increase your hour rate so much.
There is no limit to how much you can make form your article. It could end up going viral and you make thousands of Dollars from it. It may land you a speaking gig for another $10 000. It's unlimited and scalable. For 8 hours of writing there is no limit on your income.
If you want to increase your rate as a coach or consultant you have to put in more hours to earn more dollars.
Content creation is definitely not passive but it is highly scalable.