A takedown is practically inevitable if Jones grabs onto Tyson. The odds of Tyson accomplishing something [stopping a Jones takedown] that decorated/accomplished grapplers/wrestlers were unable to do is close to zero.
Also, if Tyson is on his back (or on the ground for that matter), a Jones submission is very very likely. Tyson has never defended a submission in his life, while Jones just recently choked out an experienced BJJ black belt [Machida].
Tyson has a SPLIT SECOND to land something significant before he gets thrown on his back. Do you really believe that he has a very good chance in that time frame? IMO, It is possible, but unlikely.
Finally, like I've said, an MMA based skill set translates a ton better to a street fight than a boxing skill set. You'd be dense to think otherwise. Boxing is a very limited form of fighting, while MMA is a varied and more complete form of fighting. A boxer's main skill set consists of punching, while an MMA fighter has punches, kicks, elbows, knees, submissions and wrestling. Based on the aforementioned statement, you tell me who has the upper hand in a street fight.