He was the baddest bodybuilder on the planet for almost ten years. One of the top 5 in history, if not the best.
Past champions would have retired, put the shirt back on, and never taken it off again, to keep the legendary status intact. Ronnie isn't taking that route. In this age of online sales and global marketing, he's still making a ton of $ from endorsements, guest posings, and the promise of possibly competing again.
He's trading legendary status (walking away at the top of his game in 2006) for a big pile of cash. It's every man's right to make that trade-off. Joe Montana should have never suited up and played for Kansas City. But the $10 million (or whatever he made that season) was probably worth it to him. jordan didn't have to come back after pwning the Jazz to leave on top - yet the love of attention, the sport, or money got him to put the uniform back on and play mediocre for a modiocre team.