Season 1 focus was on the survival of the 815ers, and the goal of getting off the island. The flashbacks were used to give us background on the characters lives in order to tell us whether they could bond together for a common goal.
Season 2 added the big mysteries of the Hatch, Dharma and the Tailies. The significance of these major elements has been muted this season: in retrospect, Dharma and the Tailies role was to provide red shirts.
Season 3 got us deep into the Others, Walt and Desmond's mind travels. Walt's "special" nature has been written off. Desmond's mind travels turned into total time travel by Season 6. The Others have turned into marching drones to red shirts.
Season 4 introduced us to the freighter crew, hope for rescue, who ended up as more red shirts.
Season 5 introduces us to the next wave of red shirts, the Ajira 316 passengers.
If you strip away the past seasons major mystery elements, minor plane crash survivors, the Tailies, Dharma, the Others and freighter crew - - - they were all disposal red shirts.
The current end game shows us that the stories of Egyptian ruins, the Black Rock crew, Dharma, and the Others are really immaterial or irrelevant in the Jacob-MIB saga. It is hard to believe but in reality Season 2 through Season 5 appears to be mostly red shirt filler and not connected to solving any of the real island mysteries.