there will be no plugging at all. The future is wireless.
A large screen is still a nice place to attach your phone to, instead of a dedicated docking station. At least it can provide a lot of electric power. Also, it's a reasonable place to put your phone's camera so that it's looking at you.
We have a tech event here in Brazil that attracts about 8k people. Its impossible to use wifi reliably during the event and sometimes even bluetooth suffers.