How does cryptovoxels (or any dApp game) break even?

Doesn’t each call to a smart contract cost money? I logged onto cryptovoxels, my first time in a dApp game, and saw other characters moving around.

In something like Fortnite, every player’s device sends updates to a server so that server knows where everyone is. Then, the server sends the updated game state out to all the players. This happens constantly. Hundreds of times per second.

So, how can any dApp afford to update every player’s state in real time if each call to a contract cost money?

Sorry for the noob question, trying to wrap my mind around this!