My father in law sold solar in the 70s. His take is that it failed for the same reason it fails today. For most consumers in most environments, it makes no economic sense whatsoever, even with tax incentives. The short total lifespan, rapid aging of the cells, expensive maintenance, and risks of roof damage over time, altogether reveal costs that typically are not advertised but remain obvious to most consumers. That's aside from the unsightly appearance of the cells.
In environments with more expensive power grids and higher temperatures they appear to be a suitable economic solution for the consumer. E.g. Phoenix, AZ.
>His take is that it failed for the same reason it fails today.
If your dad thinks solar is failing today I'm not sure he's a very reliable source of information. Solar has been growing exponentially since the mid 2000s and shows no signs of slowing down - the average year over year growth rate in solar capacity since 2016 is about 26% (doubling every three years). The most common error in understanding and forecasting the growth in solar capacity is underestimating future growth - every IEA prediction for the growth of solar for the last 10 years has been significantly higher than the previous year's prediction, and also a dramatic underestimate of the actual installed solar capacity. Experts in this space have been predicting that the solar exponential will level off next year for a decade, and in all likelihood they will continue doing so for another decade.
I bought my first set of Solar Panels 33 years ago. Those panels are still on the roof, have had zero maintenance, and are still happily running my small fridge.
The Battery story is somewhat different. My first set of batteries finally died a few years ago. Likewise I've probably replaced three or four inverters in that time.
Whatever, my off-grid Solar power system has repayed itself many times over.
