If they paid 80%, would they still have a viable business as more people ran solar? They have to pay to run and maintain the grid. That money has to come from

If they paid 80%, would they still have a viable business as more people ran solar? They have to pay to run and maintain the grid. That money has to come from somewhere. For people on solar and battery power, the grid is a backup, but I don't think we can have this incredibly expensive backup system running to our houses for low cost. I could see a future where the grid is no longer viable, and people run solar and batteries with diesel backup.