It is cheap because manufacturing was subsidised by cheaper dirty coal-fired electricity. Solar panels today are essentially overpriced batteries that require years of time and sunshine to discharge. 10 years ago most solar panels barely returned 50% of the energy expended to make them. At least we seems to be getting close to the breakeven point.
P.S. I really doubt that the panel will last 25 years, and the battery is likely to go poof even sooner.
The battery is Lifepo4 chemistry with a good solar controller from electrodacus.com. I typically drain to about 65% so these are considered shallow cycles.
I think the battery will go for 15 years & the panels too. So 25 years was a bit of a stretch but 15 years electricity for $500 was pretty OK.
Solar energy really is cheap.
There are many parts of the world where it makes the most financial sense.
P.S. I really doubt that the panel will last 25 years, and the battery is likely to go poof even sooner.