Both those channels are simultaneously among my favorites and drive me nuts.
Their presentations are fantastic, but fairly often the steak is all gristle and no meat.
But a podcast made a good point (paraphrasing):
"You're going to struggle if you make a youtube channel for the Spocks of the world, the people on the pursuit of knowledge and learning, because they aren't a lot of them. The reality is most people aren't Mr. Spock, they're Homer Simpson. That's why the channels made for Homer Simpsons tend to grow."
I'm not suggesting either of those two are dumb, they're obviously smarter than I am since they're doing a lot better than I am, so maybe by comparison, I'm the Homer... but... I watch their stuff and visually it's beautiful, but more often than not I wish their content itself was richer and more filling.
Wow that was really off-topic mini-rant, sorry gents...