Revealing mistake: In the park after the bad guys have been defeated and everyone starts returning to the museum, watch the T-Rex closely. In the overhead shot, he seemingly "floats" right through the branches of the trees which he normally would be moving. (01:34:50)
Revealing mistake: When the T-rex launches the table away, a couple of papers on it don't move a single inch, revealing they're glued to the table.
Revealing mistake: Towards the beginning of the film when Ben Stiller looks at the photo at him and his son, you can see that the photo is a fake. Ben and his son cast a shadow on the shadow behind them.
Revealing mistake: Obvious fake snow when Cecil runs away and the cowboy shows up in the remote controlled car.
Answer: The tablet did not extend life (the guys grew old there, remember), but gave more energy to those affected. As for stealing it earlier, that would not have been possible as they would have been the prime suspects. The best way to do the crime was to pin the rap on somebody new, like Larry, after they had retired.
Scott215
That's a seriously long waiting game.