Boy, you could sure tell that Jeff Probst, host/producer is still bitter about Na Onka and Purple Kelly quitting the show. When he introduced the jury last night, he referred to them as "the two quitters". They probably screwed up the show's agenda with their actions.
Well the show's "agenda" is drama, so if anything they helped it.
Remember, this isn't a live weekly event (although that WOULD be interesting)
It's mostly post-produced, so even if they had extra quitters, or some week with no eliminations, they just craft a story board to ensure they fill up their episode schedule. Sometimes they have to stretch or compress events, like if they want to have a romantic element to a Feb 14th episode, or they want to create a cliffhanger before the usual mid-season clip show.
And for all the talk of immunity and competitions, a lot of the events boil down to carnival games like ring toss or solving a toddler level puzzle board. I'm sorry but even on restricted diet and sleep, tossing a ring hardly compares to something like dragging the gulliver dummy. Personally I like to see the more physical and demanding competitions, or ones where there are choices to be made such as taking a shortcut or trading off risk and reward.