They are not talking about Juliet specifically, but…
TVGuide.com: At what point did you decide: We really need to set an end date for the series. And why?
Lindelof: For us, the primary belief in the first season of the show was that we would not be able to sustain this premise forever because that’s what the story tells you. If the story starts with a plane crashing on an island, the story’s going to end when the people get off the island, and for us, the process of keeping them from leaving the island was going to be very finite.
By early in the second season, we engaged in a series of dialogues with the network, saying, hey, these flashbacks are not going to last forever. Once we answer the seminal mysteries of what it is that Kate did or how Locke ended up in the wheelchair, why Hurley ended up in a mental institution, then that phase of the story is done and we have to move into the next phase of the story, which we knew was basically the flash-forwards and the story of the Oceanic 6. We didn’t pull the trigger until we were allowed to move to the inevitable conclusion.
We always did our best to make the show great, but when you’re halfway through Season 3 and you’re doing episodes about Jack flying a kite in Thailand, then the network finally said, “Oh, this is what you guys were talking about.” So we were able to agree upon how many episodes were left and at that point we knew exactly how much time we had to arrive at our destination.
TVGuide.com: Have you always known what the end of the series would be? Has it changed at all?
Cuse: Always is the operative word. We developed a mythology, as I said earlier, in the first season and between the first and the second season, and we’re actually moving toward that exact end point. I mean, that has not changed. Certain details of how the show ends have evolved over time but that’s mainly on a character level as we’ve gotten to know the characters and seen how the actors interact. So there are parts of the ending that are still living and breathing, but the actual mythological endpoint has been constant since we developed the show.
Source: TV Guide
6x01 LA X - Lost - Season 6 - Season 6 Spoilers