A Tesla coil operates between 50 KHz and 2 MHz. That's a big difference from 50 Hz. Sending energy wirelessly through the air requires high frequencies in order to radiate rather than need a conductor like wires. You can't get 50 Hz to radiate because it is too low a frequency to go more than a little bit outside of the wires. Huge amounts of power sent wirelessly at the Tesla frequencies would actually be quite dangerous as any metal object could act as an antenna. Not exactly what I would call safe. It would probably also interfere with all manner of electronics and other wireless communication so it's not well suited for modern times.

Electricity operates at 50hz , 5G works in gigahertz

You are really showing your ignorance here. Electrical power grid in the United States uses 60Hz alternating current. This is arbitrary, depending upon the speed of rotation of the generator's (actually an alternator) armature. It can also be converted to direct current by diodes, or by oscillating devices into any other frequency desired.

Did you know that 5G simply stands for the "5th generation" of cellular telephone technology, and is being deployed on a variety of different frequencies?