Bandwidth is a limited resource. McDonald's isn't charging you for the internet, but that doesn't mean it's free (they pay for your use). Basically, cost is a way of rationing it because, otherwise, we would run out of bandwidth. And, while ground lines are getting cheaper, we're pretty close to hitting a ceiling when it comes to airborne internet (e.g., the kind on your smart phone). We're literally running out of usable radiation. So rather than things constantly improving, we may have hit a peak of unlimited internet that will be scaled back to the point where we can look to right now as the golden age of internet usage.