Nicknames?

Nicknames were given to people to make their names easier to pronounce and to create a familiarity with them. Thus, David is Dave, Robert is Bob or Rob, and so forth. All of a sudden, people seem to prefer the lengthy names.

I know a guy named Anthony who prefers to go by Anthony, not Tony. A guy who prefers David over Dave. A guy who prefers Michael over Mike. Indeed, as Michael Phelps's mother was cheering him on, it wasn't with exhortations of Mike, but Michael.

Why the trend? I couldn't say, but it's something I've noticed.