It's happening already. I have Comcast, and in my area, as of 2 years ago, they ditched the data caps entirely. I usually hit 750GB or so a month and my bill has no change whatsoever. I know Comcast is shit, but in the boondocks where I live, it's either them or shitty local DSL. It's very likely that in 10-15 years those caps, as sizes increase on things, will vanish everywhere, 3rd world nations like the US included.
That's not my point though. I'm not saying that DLC is filling their pockets, just that it has become accepted - or at least begrudgingly accepted - by the majority of consumers over the past 11 years. I'm sure it still accounts for a small percentage of their business, but all that matters is that they've convinced consumers that its acceptable and they can get away with it to hide their laziness.
Wouldn't matter if you think of it in the TV network analogy I initially used. Think about it: In the 80s/90s/early 2000s if you wanted TV, what did you do? You paid one of the local TV barons $xx.xx a month and they gave you access to the channels you wanted (in a package deal of course). You didn't pay Disney, Nickelodeon, MTV, CNN, or FOX individually, you paid Comcast/Warner/whoever. That's why cable is in such a bind know, since to be fair, they can't charge per network because failing networks people don't want anymore (Like ESPN) are holding them back from de-bundling/packaging channels.
But anyway, it would be the same as that. You wouldn't pay Sony or MS or Blizzard to play their game library individually, you'd pay "Huge Network Monolith" $xx.xx a month to subscribe to a tier/package/bundle that has the companies you liked in it. So you could say "Oh, tier 3 has Sony, MS, Sega, and Blizzard, but not EA…but I don't need EA, so let's stick with tier 3". It'll just be like TV. We just need to figure out who the "Huge Network Monolith" will be. Google? Maybe.
As I said, TV buying will be different 20 years from now. It'll be more of an uplink to "the network" and will be used to streaming more than just movies and shows. Just like how the first TVs had external antennas or antennas you had to purchase and eventually had them internally, you'll see the same happen with set top boxes.
Console manufacturers will like this because it doesn't pay MS, Sony, or Nintendo to plan, develop, market and test new hardware every 5 or so years. They'd rather just focus on software, especially if it's given out completely digitally with no need for physical alternatives.