In a recent interview, Naughty Dog co-president Evan Wells discussed its next title from their "Uncharted" series. He also reportedly teased that "Uncharted: The Lost Legacy" might be the developer's last game for the franchise. Wells claimed that "doing an 'Uncharted' after this is unlikely," after he discussed about the latest game in development. It seems like the game studio is still deep thought about whether they will stop it there with "The Lost Legacy".
However, the developer also clarified that their decision is not yet final and that they might consider another follow up in the future. Sources suspect that the developer is currently hard at work with a sequel to their post-apocalyptic shooter "The Last of Us: Part 2" Game Informer reports that Wells reasoned out the absence of a secondary studio, which of course obviously means manpower, as the reason for their undivided focus on another title for the moment.
Given Naughty Dog's reason for their hesitation to develop another "Uncharted" sequel, it seems like the studio has not given up on their beloved action adventure series. Several reports have revealed that the developer also encountered the same situation during the development of "Uncharted 4: A Theif's End". However, it was speculated that their goal prior to their work on "Uncharted: The Lost Legacy" was to hopefully establish a new game franchise.
In an article from Gamespot, it was supposedly confirmed that the "The Lost Legacy" will feature the largest game level designed by the developer for an "Uncharted" title. The game studio confirmed that it will be set in the Western Ghats mountain range, which aims to surpass the Madagascar level in the fourth game in terms of size.
Given the action adventure series' success, Game Rant speculates that Naughty Dog could be hesitant to flood the market with another "Uncharted" game too soon. It seems that they are worried about the so called "franchise fatigue" that might push fans away from the series. However, It seems like "Uncharted: The Lost Legacy" might be enough to tide fans over until "The Last of Us: Part 2" comes out.