It's not such a wild idea. Although Earth may not be as big as the world Zhou Tian is currently in, when it comes to human numbers, they are more than a hundred times the number of NPCs in his current world.
Forget about other countries, just China alone has a population of 1.3 billion. Imagine if one-tenth or even more of this population were to enter Zhou Tian's world. The pressure it would create on the monster side is shocking.
Don't think that having over a hundred million people playing the same game is a huge challenge. The number of online game players in the world is definitely more than one or two hundred million. And with the new technology in that game, it can attract 99% of the internet gamers to choose that game.
Eventually, as more and more players enter the game, widening its reach, even those who didn't play games before may be attracted to it. Finally, with the draw of various new technologies, it is believed that the people who tried the game won't easily quit.
