It seems to me that by the 1970s all the groundwork was there to start a solar panel revolution and that the major reasons it didn't happen were political and social, not technical.
Keep in mind that I haven't done any research on this subject yet, I just thought of it a few days ago and I'd love to hear input from anyone who is much more informed on the subject than I am.
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.
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.