Do you ever get tired of being wrong? Overeem wasn't in his Ubereem phase in 2014, he had been off roids for a while by then and his body finally got used to being off the juice again and everyone was calling him Econoreem. He was fighting at a slower more deliberate pace and was using his wrestling more than he was when he was full of juice.
You can't garentee shit, Jones never fought someone like Overeem in his career that has strong wrestling, sub grappling, better striking, much more power, is a threat to finish in the stand up, with GnP and with submissions. The Overeem that beat up Sergei was pretty much the same one that beat up Jones in training.
Overeem got off the juice in 2012 and his body wasn't used to that till 2014. You can see it in his fights with Bigfoot and Browne where he was trying to fight as if he was still on the juice which caused him to completely gas in round 3. He looked much better against Mir a year later, he had less muscle mass but his cardio was much better.