Judging by the Teaser, most of the people would know this probably is going to be last uncharted. And most of them would argue that it isnt, Sony wont kill off their major franchise. Both of them true, I believe this will be the last Uncharted for Nate, but Uncharted as franchise will continue with a new protagonist, maybe Troy Baker at helm. So here is my main topic. I assume everyone has a different theory on why this could possibly be the last Uncharted, my theory is because of Amy hening and Justin Richmond, Wrtier and director of UC3 and the group that they created over at Naughty Dog which include Nolan North, Emily Rose and Richard McGonagle.

As everyone knows Amy Hening is now at Visceral Games making starwars and she has roped in Todd Stashwick (the VO guy from reveal teaser) to join her. So now the core group no longer part of the franchise I dont see Nolan North and rest of the cast continuing the franchise (Orginal Spiderman dilemma), which might have lead Neil and Bruce to write down Nates final chapter, go out with a bang. And after the TLoU I have a feeling troy baker might lead the next iteration (but that is after they give Uncharted a rest) or Just for fun sake I would love to see the Adventure of Chloe.. it wont be surprising if ND have roped in Troy baker for Todd's part.

So do u guys think. this will be the last uncharted and ND will replace it with The last of US series.. or is just the end of Nate, sully and elena and series will continue with a new protagonist. Maybe neither of them we will see them in Uncharted 5?

p.s. I m not a fan of Troy Baker :D

UPDATE

Here is somewhat of a confrimation from Drake himself (Nolan North), it is indeed going to be the end

Speaking to IGN, Nolan North explained that as far as he's aware this is the last title that Naughty Dog want to do in the series, and admitted he hopes no one else tries to continue the story without the studio.

"It’s bittersweet but at a certain point you want to go out on top," North told me. "If this is the last one indeed, and I believe it’s the last one - nothing’s confirmed, but I believe it’s the last one Naughty Dog wants to do, in which case I hope somebody else doesn’t pick up the mantle because they’ve done it so well for so long - but yeah, it’s one of those things where you just have to cross that bridge when you get to it.

"I like the idea of going out on top so we better do a hell of a job with this one… and it’s already looking pretty good."

Source: http://www.ign.com/articles/2014/06/12/e3-2014-uncharted-4-star-thinks-its-the-last-one

I don't think this is the last uncharted and Nd aren't gonna turn Tlou into as long a series as uncharted. They'll likely make uncharted 4 then a new IP then tlou2 and offset uncharted or bring it back towards end of current gen in a deep story

If it make $ than they make more uncharted. If no $ is made than uncharted goes poof.
See Halo franchise and Mario for more details.

God no. Why would Sony end their biggest franchise and their most likable character? The perfect example is Halo.

So much of Nathans life could be made into numerous games. 

When Uncharted 3 was announced I expected it to be the last game in the series, the magic number three you know. Trilogies. But since it wasn't and a fourth one is coming now I will go with 6 games. :P

Just, because.

EDIT: Also I think that it would be nice, if they made 6 games and then changed the main character. Kind of like with Bond movies. I would have liked them to do this already after the third game, but one part of me really loves Natan Drake and Sully, so it would also be really shame if they changed.

Aslong as Naughty Dog continues to make amazing games i am fine with their decision. I am glad i got to play all the Uncharted's up and until now and platinum them all except(Drakes Fortune), but i have had lots of fun with this series, to see it end will be heartbreaking. Ultimately New IPS will be born and that Naughty Dog magic will be reimagined. 

You better not call it that. The last time Sony had the words "The Last" in the title, the game never came out.

Can any franchise ever gracefully retire in gaming? Right now I can't think of the last time one purposefully faded out and stayed gone.

The one that got more than 200 game of the year awards ? it was awesome ^^

Uncharted 3 should have been the last, the developers should have been working on something new and exciting yet the start of this generation we are mostly getting sequels and remakes it seems. This gen really is living up to the just like last gen but with more power.... Tim Taylor would be proud.

Of course, if something makes money they why stop there. Just look at Fast and Furious film series. :P I'm sure they will continue to make more of the series but at some point it won't be Naughty Dog making it anymore, I'm hoping after this entry.