There was a joke from the 80s: soon the whole trading floor will be replaced by a computer, a man and a dog. The man presses the button to turn on the computer every morning. The computer operates all of the transactions and settlements automatically. And the dog is there to bite the man if he touches any other button.
30 years later, still no dog on the floor!
The factory of the future will have only two employees, a man and a dog. The man will be there to feed the dog. The dog will be there to keep the man from touching the equipment.
I believe the remaining ones are effectively TV studios for business channels, so they have a completely different purpose now.
But I don't think anyone believes those have more than a couple of years left in them.
Electronic trading does change dramatically the shape and profile of a trading floor. Introducing central clearing with margining not so much.
You won't achieve electronic trading anytime soon on products where there are perhaps at most 200-300 buyers in the world, must of who are only interested in buying big chunks.