The social landscape has changed for the worse. People no longer want to connect with friends, they want to show off how better/popular/wealthier they think they are.
Even if someone relaunched that era's Facebook without all the crap I wouldn't be surprised if today's society still manages to make it toxic.
It is the gamification factor. People is optimizing their behavior to get more likes not to get better connected.
"Given the opportunity, players will optimize the fun out of a game" summarizes quite well the situation.
Wearing a suit feels a bit pompous, but it would be interesting to hear what the musicians and conductors think about the audiance's attire. I assume most don't care.
That said, I'd encourage anyone to go to a concert wearing jeans vs not going to a concert. The music is what's important.