It's also interesting where we choose to draw the line for what's considered "low-tech." The most common method for producing monocrystalline silicon was invented in 1915, and doesn't produce that much waste or involve exotic materials:
Oh, ok. I don't think PV fare any worse than CSP on that. In fact, CSP needs so many independent engineering domains that it's probably among the worst things you can choose on that metric.
https://en.wikipedia.org/wiki/Czochralski_method