Camille Victoria's guess was spot on.
After the Freedom Day competition ended, there was no way that the supercomputing center, which was used to upgrade Mavis, wouldn't be put to use, right?
Normal player growth doesn't require supercomputing; the fuzzy computing power of their brains is more than enough to handle their own needs.
But Lincoln knew that if he didn't give Mavis some new tasks, she could use the 60 billion plus supercomputing center solely for browsing the internet, eating melon, and gossiping.
So Lincoln simply imitated the competition map and created a public version of the open Metropolis map.
Because it doesn't need to maintain hundreds of virtual cities that can accommodate tens of thousands of players fighting simultaneously, like the competition, the computing power is greatly surplus, and finally expanded to a capacity of 100,000.