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.
Electric bills have two components, the supply cost and the delivery cost. The supply cost is what the electric company should be paying for electricity it buys from the home owner. But the electricity the home owner buys back should include the delivery cost.
In effect, the utilities are subsidizing home generation, which may make sense for now, but is not a plausible end game.