My perspective comes as somebody who understands broadband as a business.
I pull "12-14 mbps" down through Comcast supposedly.
I pull under 500k off of PSN at very best. It takes 12 hours to download a demo or better.
Imagine 1 million people trying to download Halo the day it came out off of Live. Everybody would be getting 50K down max, servers would be so overloaded.
More than half the geographical country has to settle for either DSL, Dial up or Satellite. Some of these people could throw a stone and hit a Gamestop or Walmart but it would be physically impossible to download the latest game. Even if Microsoft upgraded their servers X1000.
Most ISPs are also starting to cap usage, so now people who manage to download too many games would be forced to pay overage fees. Can you get overage fees for spending too much money at the store?
Plus you couldn't take games to a friends house anymore like the first 30 years of gaming?
Once every single person in the entire county is connected directly to fiber or some much more advanced ISP getting 50+ mbps, there would be a slightly better chance.
So yes, maybe in 50 years....