But since the entire point of the 5th season was to rescue everyone on the island and bring them back, now they leave people behind again. And Jack basically wanting to commit suicide because of the guilt of leaving those people behind. Now Hurley is expendable? Nope, sorry, doesn't sit well with me.
What? How did you come to the conclusion that Jack was wanting to "commit suicide" due to guilt of the people left behind? Seriously, I have ZERO idea where you got that from. Jack's inner transformation was not all that different from Desmond's sudden enlightenment and the realization of what MUST be done...and him being OK with it. Jack's transformation took a lot longer, but he reached the same place...he knew what must be done and was OK with doing so. No "guilt" necessary.
And as Casey has said numerous times,
Hurley WANTED to stay behind. Why that doesn't matter to you and you can ONLY see it as the others viewing Hurley as expendable, I don't understand.
As for the point of season 5...Jack already said that the reason he came back was because he thought the island could "fix" him ("I came back because I was broken"). Do you remember, in season 5, when Juliet and Jack had this exchange in the bathroom?
JACK: I came back here because I care, Juliet. I came back here because I was trying to save you.
JULIET: We didn't need saving. We've been fine for three years. You came back here for you. At least do me the courtesy of telling me why.
JACK: I came back...because I was supposed to.
JULIET: Supposed to do what?
JACK: [Scoffs] I don't know yet.
JULIET: Well, you'd better figure it out.
So that kind of puts a dent in your theory that all of season 5 was geared around getting everyone off the island, doesn't it? Jack may have
said that's why he went back, but it's made DAMN clear in that exchange that it wasn't the real reason he went back...that Jack didn't know yet why he came back, only that he "knew" he was supposed to. And as mentioned before, Jack further explains to Hurley that the underlying reason he came back was because he was "broken" and thought the island could "fix" him. No talk about getting everyone off the island that was left behind before.
Why did Hurley come back? Because Jacob visited him and set his path in motion...as Jacob said, some people just need to be told directly what to do, and Hurley was one of those people. Why did Sun come back? Because she was made to believe Jin was still alive, and she ONLY went back for him. Why did Sayid go back? He was forced lol...Ilana had him handcuffed and under arrest. Why did Kate come back? To find Claire and return her to Aaron.
Again, the idea that the "entire point of season 5" was to get everyone off the island is false.