This is a good question - there are fairly high imposed tariffs on solar in the US[0] but I think the labor is the big part. Over here in the UK, solar installation would cost about $12k dollars, so quite a bit cheaper, but still not below $10k.
One thing that isn't super obvious from the article is that a lot of it is talking about industry solar panels rather than rooftop. The overheads of installation etc get a lot smaller if you're installing a whole bunch at once.
This isn't to say that installing solar panels on your house is a bad idea - they normally pay for themselves after something like 10 years from memory, so are similar to double glazing.
One thing that isn't super obvious from the article is that a lot of it is talking about industry solar panels rather than rooftop. The overheads of installation etc get a lot smaller if you're installing a whole bunch at once.
This isn't to say that installing solar panels on your house is a bad idea - they normally pay for themselves after something like 10 years from memory, so are similar to double glazing.
[0] https://www.energy.gov/cmei/systems/overview-trade-and-polic...