You hit it on the head!
It really seems so obvious. If somehow the population were limited on Earth there would be enough resources, including education, for everyone. And then all the interesting stuff could be done.
And if the population isn't limited, the humanitarian and political efforts to calm a riotous underclass, both people and nations, will preclude much of the "fun" stuff. And it will only get worse.
I don't know why that is so hard to see, I really don't.
Arf