[tsjackson]

Inverter failure is real, but the industry standard has risen to 12 years for string inverters, and 20-25 for micros. Even for string inverters, most of the residential/small commercial market has moved to using optimizers for voltage regulation, which means the inverter itself is a lot lighter weight/cheaper.

Backup batteries are still relatively rare, as they should be - they are fairly expensive as backup power. Most systems remain grid tied. Smaller systems don't require retail net metering for a solid payback, since almost all of the energy is used as it is produced.

Roof repair is again, real, but not as likely as you might think. Asphalt shingles under an array are protected from wind, and even more importantly, heat. They degrade at half the rate of the rest of the roof. Assuming 12-15 years for roof replacement, you will hit the module warrantied life of ~25 years before you need to replace the roof underneath the array.

Cleaning the panels really only comes into play when the pitch of the roof is relatively shallow (3 on 12 or shallower). Otherwise rain will clean them fairly well. A lot of people won't have any trouble walking such a shallow pitched roof, and will simply hose the panels off once in a while.

Also, in general, the price of modules per watt is about half of what it was 5 years ago. Peripherals are a major component of the improved economics, but module prices themselves have mattered just as much.