There are all kinds of complications - commercial solar isn't dispatchable so it does tend to get lower rates than most other sources. In my jurisdiction residential (net metering) customers are only allowed to install a certain numbers of panels - corresponding with household energy consumption and assumed production levels (i.e. your monthly bill will never be negative - at lowest you'll be paying distribution charges and 0 for consumption). With low levels of residential solar installation, locally installed panels can help balance the grid as it is consumed on distribution lines and doesnt need transmission lines (conversely, high levels can unbalance the grid).

> if net metering lets residential solar owners get paid more for the energy they produce than solar farms would be paid, I don't see how that's anything but a subsidy.

Paying them nothing would be even more unfair (and that's the only option available where I am at least - net metering or no household generation)