Uncharted is the kind of IP that could theoretically go on forever without people getting bored with it, as long as they space them out enough (like Mario or Zelda games basically).
Unfortunately, ND kinda wrote themselves into a corner with U4, though I personally think they already started going in the wrong direction with U2, when they brought back Elena and made her Nate‘s permanent love interest. She was a much more fun character in the first game, but then turned into a bit of a nag in subsequent entries. Imo it would’ve been better if there was a different love interest for Nate in each game, similar to the Indiana Jones movies, or James Bond. Chloe was perfect for that role in U2, Elena‘s inclusion wasn’t necessary. U3 and 4 should‘ve each had different girls as well. The fact that Golden Abyss had a totally new female lead was the best part of that game.
Nate the womanizer > Nate the family man
The only way around Nate’s retirement is if future Uncharted games are prequels, similar to Golden Abyss. I absolutely do not want a ‚one last job‘ story for U5, nor do I wanna play as Nate‘s daughter. I guess a Sully prequel would be ok in a pinch, but I really would prefer to play as Nate again.
As for TLoU, I‘m one of those who think part 1 didn’t need a sequel in the first place, at least not with Ellie and Joel again. I would’ve preferred a new story with new characters, totally unconnected to the first game. I hope that‘s what they‘ll do if they’ll ever do another TLoU game.