I would point a couple of other aspects than bandwidth. Do you believe the average folks will switch from acquiring physical discs to some illusory internet delivery, when for a decade whatever form and shape it tried to take it was marred with DRM, and all the myriad of schemes for the big money studios to make even more money when nobody really cared for what you got for your money? No way.
I do admit the plastic has its weaknesses but the biggest one is plastic itself not some rival method of delivery. When you say plastic you mean discs, which in one form or another are the same for years, because of the utter incapability of the industry (music or movies) to change, for fear they will have to replace the zillion of current players which are pretty much the same, short of diodes, a chip and 3 wires. Think what you can do with the plastic. Why didn't they create a format/case that wouldn't require the unprotected surface to be handled; something like a caddy, an enclosure (that could replace the jewel case entirely). Noooooooo, that will also require to change the loading mechanism everywhere, and more important will create a product that will last forever, short of running a truck over it. It needs to be frail, to break, to scratch, so you go buy it times and again while they laugh all the way to the bank.
As long as both the need to have it and to produce it will exists, the plastic will reign supreme, regardless if we have fiber, your private satellite orbiting atop of your head and the likes.