The current system lets the home owner use the power grid as a battery, storing excess energy for later use. And this battery is free. But it's not free - someone has to pay for the power lines, meters, and generation or storage capacity that makes it work.
The power grid is only conceptually (and billing wise) treated as a battery. It isn't electrically. The grid doesn't have a set of batteries (and AC-to-DC converters) storing excess solar panel output for later use. Instead, the excess power is consumed by nearby homes that don't have solar panels (the path of least resistance). Billing wise, it is treated as a battery (in a majority of areas), because that makes the billing simple.
I see roof-top solar as a convienence for the generators. It effectively removes load during daylight (ie peak) times, and transfers the load to nighttime (ie, non-peak) times. It smooths out the day/night variances in generation. That only works as long as the roof-top solar production remains smaller than day/night variance, but that's the case we're dealing with now.
Aside from that, I (living in SoCal) do pay a delivery charge on my monthly bill, regardless of my generation or consumption of power. I've no idea how it's computed, and it varies month to month. It doesn't seem to be related to how much I generate or consume in a given month. It's a couple dollars, so I don't really care.