I would have to say that drawing (or purchasing) a limited tag in a unit with super genetics, antler growth, and all the right conditions plays a major role in successfully harvesting a mondo buck! Learning access routes, viewing spots, bedding, feeding, rutting, migratory routes, etc definitely up your odds of finding and shooting a buck of a lifetime!
With that said, I would say that if you don't ever draw a tag and hunt units that have B&C potential your odds of getting a super buck are pretty poor! As many of us know, it may take several seasons (tags) in a good unit to harvest a super buck! Obviously, the more tags and time you spend researching, scouting, and hunting these areas the better!
Some units and areas within a unit may be different than others at different times of year...units with a migration, high alpine vs late season...may make it tougher to scout for a particular buck because he may not show up or be in the area at certain times of year. A particular buck may be at 10,000' in August but at 5,400' in November? Obviously it is possible (and a lot easier) to scout a particular buck if he is a resident in the area year-round.