@2much and @Mayhem
Bingo. That has been the argument I have made over and over. Most people don't care about the environment, they care about their wallet.
I had the same fight with the two women in my life regarding a Ford Expedition we had. Every single time it went to get gas in it, I heard about it. I pointed out the minimal amount of miles driven per year. They didn't care. I did a spreadsheet showing the return. That moved the needle a pubic hair. I have a penis, therefore I lost.
In regards to solar, people are using so many non-economic excuses to not do it. I tend to chuckle. Why? Because I don't see them dumping their car as soon as it gets to the 37th month and out of warranty. Somehow, someway, that solar device is going to die the day out of warranty, but the car will not.
Solar panels do degrade. If you look at the warranties, it is efficiency at the warranty point. Most will guarantee 80% iirc to 20 years. Think that through. If it goes below 80% at year 21, uhh, ok. What is the worst case scenario? Replace ONE panel. That will probably get you back to 80% for a bit. When it dips again, replace another. Panels are dropping in price.
The electronics (inverters) will probably make it 12 to 15 years. This is such a variable cost depending upon what you want the inverter for.
There is a guy on Youtube, HOLY SHIT, he does a great job of explaining and setting up all of these systems as a DIYr. Look up Will Prowse. He reviews products, does battery reviews, etc.
But I do like what Mayhem pointed out . . . the next guy.
This goes back to the chuckle part. People are thinking that these are sunk costs and have no tangible value on their property! You remodel a kitchen and it gets what percent back when you go to sell? :) Same concept. There is a CapEx issue on the asset and then a value at a point in time, it is not zero.
The last house I had, it had a 1970s solar blanket thingy on the roof and it was set up to try and heat the pool. When I found out it didn't work, I pulled it. In hindsight, I should have replaced it. It probably would have cost me $2500 to replace/upgrade things. At that point, I could have a pool heated all the time. This means little to those that live in Florida, but here, heating a pool is hard because the air is cold. That would have had a quick ROI!
There is also the qualitative issue that people are leaving out. Again, being from South Florida, we call FPL, the power company, Florida Flicker and Flash. When we moved here, people freaked out because we showed up with about 20 different UPS's and our power generator! When you don't have power for 2 weeks because of a hurricane you understand the quality of life issue. How do you put that in a ROI?
But if you are really interested in this stuff and considering going 100% off grid, look at the Will Prowse guy. Last I checked he went completely off grid with storage and charges his Tesla from it! The math worked out for him.