Just as they are with stilettos, millennials are doing everybody a big favor with their attitude towards business suits. Whoever decreed that wearing a full business suit was necessary to work in an office had strange ideas about fashion. They're too hot, they're uncomfortable, they scuff up too easily, and they're expensive. On top of that, ties are the most unnecessary invention in the history of clothing.
Wearing a suit used to mean you were successful, but millennials grew up watching a different set of successful millionaires. Bill Gates very rarely wore suits. Steve Jobs never did. Mark Zuckerberg doesn't. The trend has turned on its head - businessmen who don't wear suits are seen as being too successful to need one, whereas suit wearers are likely to be grasping salespeople. The time of the business suit is ending.