You are starting from the "I don't believe in rooftop solar" position and are contriving arguments to support that position. Your argument could apply to _anything_ with variable consumption. What if someone goes to the store once a week and only buys a bottle of wine? They benefit from the convenience of an on-demand grocery store, but if all their customers did this, the store could not exist. Should the store reject this person as a customer? No, the store's fixed costs exist whether or not this particular customer shops there or not. Nothing is to be gained by keeping them away. The same is true with power delivery, those fixed costs exist even if this solar + batteries customer disappears.
> If you don't want to pay for the convenience of having on-demand power whenever you need it, disconnect from the grid.
This is not an argument, just a projection of power. You can say this to non-solar users now.