Young people are wanting to wear suits more and more. Men are wearing suits to "business casual" events, out to night clubs, and even with sneakers and t-shirts on their own time.
90's businesses across the board, lead by Google and the other "techies", adopted a (very) casual dress code where suits were no longer necessary. In my opinion, this overly casual movement created an old-world nostalgia for the days when guys dressed like men and wore suits, and took care of business while "dressed for success".
In combination with that, some of the coolest cats in the media (from athletes, to actors, to musicians) are rocking suits on a regular basis...and we all know the fashion pull that celebrities have.
Here are some of the top players who are making suits cool again:
The Cast of the Ocean's Movies
Remember the days when hip-hop artists dressed like this:
I'd say it's been an improvement.