I don't have to explain it, Stephen King already did... Dark Tower, third book, The Wasteland.
In this ep, Daniel is searching his journal for the change, and we see a page where he has a drawing of about 10 suns. This is one of the points to what the 'science' is behind the show. I quote 'science' because it is mostly theoretical. Basically, there are 11 timelines, in each there is a Desmond, a Farady, an Eloise. Each lives almost the same life, but is off by a decision here or there, but the decisions are never monumentous to the grand scheme of life, but to one's own character. However, Desmond, because of how he was pulled from one timeline to the next with the turning of the failsafe key, has caused his decisions to affect other characters arcs, so an agent who knows how the hole between the timelines work, is called upon to make sure he follows the corrections.

It's obviously even more comlicated than that, but that is where the show is going, and the writers have tried to nudge people in that direction for a while, but people, like my belovd Aunt, who still think it's Hell, need a big push, and that is what Desmond is there for.

Yeah, you are right, people like the show for different reasons, but the science behind the plot is going to be an issue, especially for people who think it's dumb or 'gay' as I've seen written here. But it's obvious now, as it should have been that there are competing times at the center of the shows theme.