I feel like Biff being the loser outcast of the town was due to much more than him being knocked out by George. Even more than him being humiliated by the skateboard chase and manure truck, or even being an attempted SA-er and multi-attempted murderer. (Neither of those last two had any effect on his life in the original timeline because if it wasn’t Lorraine he tried to SA or Marty he tried to kill, it would have been someone) I theorize in the final ‘85 timeline he becomes ostracized because he became a whacked out conspiracy theorist. He definitely tried to get his cred back by claiming he wasn’t schooled by a human, but an alien. He’d say he saw a crazy UFO take the alien in human form calling itself Calvin Klein back home at the tunnel where he was again tricked into running into yet another manure truck. He would undoubtedly be backed up by Old Man Peabody who, in the original pre time travel timeline, was already described by Doc as crazy. He probably spent so many years looking for “the truth” and when the Betty and Barney Hill abduction happened he was the first in Hill Valley to scream “I TOLD YA SO!!” I wouldn’t doubt if he made enough noise about it that he was selected as a “random” target of MK-Ultra.

• Edited for a brain misfire *