Countries have seen cults of personalities take over, where the leader sets the culture and prevents a change in leadership until it is often too late. Sometimes this just disrupts the country when the leader dies, like in the cases of Roosevelt and Trudeau.
Going into the merge, up 6 to 4, seemed like a strong situation until Matt rejoined the crew from Redemption Island. But Rob convinced his team to get rid of their old team-member, even though the man was willing to forgive the prior treachery.
No-one on his alliance has been looking for clues to the hidden immunity idol, even though they have seen clues appear in every reward in the past and in previous shows. Worse than that is the iron grip Rob has on his alliance. He sleeps them in a separate shelter from the former Zapatera team. He instituted a 'buddy system' where no member of his alliance is allowed to go anywhere alone. And, in the most egregious example of tyranny I've ever seen on Survivor, he demanded that his alliance stay away from the fish the other tribe caught, regardless of how hungry they were. Only Grant seemed to object to this rule but he was quickly recalled by his leader.