There are numerous methods which games in the past of used to make it easier to handle. You can look to simplifying animations & models when exceeding a certain number of players in a given area found in games such as Ankama Studio’s “Dofus” or in instancing areas such as within CCP’s “EVE Online.” With enough thought put into how you handle your game world and the scalability of your hardware it should be able to handle however much you want it to handle.