#1 The Rock

It's hard to blame The Rock for walking away from wrestling and WWE very early when you consider the fact that in 2020, he's among the biggest movie stars in the world. There was a point where he was even the highest-paid actor and virtually every movie he's a part of becomes a box office hit.
It took him a good decade to reach that position, but it was a gamble he took in 2003 when he quit wrestling. We're aware that he wrestled in WWE during 2004, 2011, 2012, and 2013 (and even 2016, if you count the six-second match against Erick Rowan), but the reality is that his wrestling career at its peak ended in 2003. As you might know, in 2001, he acted in The Scorpion King in the leading role and this would eventually set up his big Hollywood career.
Given the impact he had in WWE and that it was his platform to become a megastar, we find it hard to believe that his run on the top truly only lasted for 4-5 years. He quit wrestling full-time in 2003 at just the age of 31. What was an even bigger shame was the fact that in 2003, his "Hollywood Rock" character was taking off in WWE and it was some of the best work of his career. Unfortunately, we never got to see how that would unfold.