I guess it varies, but most of all it's hit-and-miss. From what I've heard, you are basically either required to grow your audience to few tens of thousands before you can get any reasonable ad-revenue, or have enough luck to create something that goes viral. And even then you may lose your audience (and revenues) as fast as you can gain it.
On Hive the growth is very very slow, especially at start, but it's still growth. I've started to think it's a bit like a having compounding interest. If you don't make any huge mistakes (like plagiarism), you're almost guaranteed to gain a pretty sustainable income stream eventually.
I have understood the same - it isn't as easy as some people have been led to believe, which is why so very few people (in the grand scheme) can actually live off it. I have heard that many of those "influencers" travelling the world in bikinis, are actually living off their parents.
And yep.. it compounds and adds up fast. I know a lot of people who have realized this and have grown their accounts over the last years significantly, whilst still putting the effort into content.