Remember about the problem is the blockchain adopters are limited and that gives a big challenge. Not all of them are require the funds remember you can even do marketing by yourself through use some forums.
Do you know which is platform that charge a lot of fees for marketing?
I agree. It's also limited. So we're looking at a very small and competitive market. We can definitely do it through forums, but it really just isn't as efficient and scalable.
As for platforms, I think a lot of crypto sites are charging very high for CPM and also influencers have crazyyy rates; with almost invalid numbers or data to support their prices.