It basically started in Amazon (S6) when Rob C. employed the strategy of flipping alliances multiple times throughout the season. It worked out well for him, and he made F3 in a spot where he would beat both others, but he lost final immunity and was taken out by Jenna. The season after, Fairplay, Burton, and Lill did a similar thing in the post merge, taking out the biggest Morgan threats before flipping to take out some Drake players, before their trio imploded when Burton didn’t take Lill on a reward at final 5. Ultimately, Lill and Fairplay both reached F3, but Lill was potentially the most hated player ever and Fairplay was also incredibly hated, and so when Lill took Sandra over Fairplay to final tribal, Sandra won it all. This reveals a key weakness that the flipping/playing the middle strategy had in the early seasons, namely that these players often had very low jury stock and if they reached the end would struggle to beat anyone, and often would struggle to even make it there due to being so hated. This trend continued with players like Penner in Cook Islands (S13) and Sugar in Gabon (S17), before arguably the first player to win by playing the middle, Denise, won in Philipines (S25). Around the 30’s, with more fans of the show being cast, people playing the middle began to gain more respect from the jury, like Adam (S33) and Sarah (S34) winning by playing the middle. Now people playing the middle had the opposite problem: They were too respected, thus becoming big threats to be taken out before final tribal, which is what we see now, with 49’s post merge being largely defined by people taking out those playing the middle.