How do Youtube Gurus stay relevant

I've been talking to a friend and he was about to buy a course for $3k from a youtube guru and I tried to reason with him and told him that most of these make money online course sellers on youtube are nothing more than selling a pipedream to their audience

How do they keep scamming their followers and keep selling them not working business models/rehashed information and their followers keep on buying their stuff?

I'll answer that with a story from many years ago, when I used to work for an affiliate network.

Back them, there was this "you won an iphone" type of pin submit offer.
It made tons of money, and I never understood how it performed so well for so long.
As if people didn't learn to not fall for this type of thing.

My boss explained it like that:
Every single day there are new 15 year old idiots.

So, every day there are new noobs that fall for these things.

It's the same idea behind any dream selling. As long as you can portray yourself to be successful and you are selling what you're doing OR you can portray a realistic outcome w/ some type of proof, you'll always find new fish to catch.