For a deer like that to survive it had to of been protected. People have been seeing that buck for a long time on cameras and such. Low fence or no low fence.
Big bucks get big for a reason. They are smart as hell.
BS. People are smarter. People are more persistent.
Bucks are driven by behaviors they can not change.
If that buck was from a remote Canadian area I may believe he lived long enough to get exceptional. In Texas no way. He was protected some how.