Sometimes I don't know if it's the dog that wags it's tail or tail wags the dog when it's in regards to fashion primarily mens suits. If you pay attention like I do, you will notice more and more men wearing 3 Piece Suits
than ever in recent times. It may be because of the number of time period correct television shows that Hollywood produces that show well dressed men wearing them in main character roles like "Boardwalk Empire" or maybe it's the designers themselves who stealthily do their craft and are designing more of these 3 pieces style suits into their collections. Either way, you will see more of the well dressed men wearing because of Hollywood and their huge influence on fashion. These men who you do see wearing these vested ensembles are for the most part men who are more style minded and take real pride in how they look when they are out in public.
It just may be that 3 piece suits just look better because they seem to have a more complete look to them then your basic jacket and slacks versions. Watch any old period time movies or just look at some pictures of how gentlemen dressed 80 years or more ago and you will almost always see them wearing vests with their suits. It seems like that was the only way dress and if you were not wearing a vest you were not properly or fully dressed. Depending on the style of the day, the vests on a 3 piece suit may have either matched the suit fabric or would be something completely different and contrasting if style was a consideration. The main fact remains that these suits have might quite a comeback which is a positive thing indeed.