You think a map as detailed as the one you showed would take a week or two? Not hardly. If UE had all of the assets that you needed for the specific League map, maybe. But there are far too many things that needs to be remade, like turrets, the base, nexus, and everything else that doesn't have a copy-paste model. Then we get to moving assets on the map, like the minions, jungle monsters, dragons, Baron, Herald, and of course, the over 140+ champions. Getting ALL of that to the level of realism proposed here would take years based on how many people they can dedicated to this level of detail and rendering. Then they have to redo the VFX to match the ultra realism too, adding more time to the equation. This kind of endeavor is not a game mode. It takes Riot the better part of 6 months to create or VGU a SINGLE champion. To do everyone at this level is not at all within the scope of this game.