What happened in the last decade was that solar panels ("Module" in this graph)
got very very cheap. They used to cost $3 per watt in 2010, but now only
cost $0.3 per watt.
This extreme price drop happened thanks to technical innovations (such as
commoditization of PERC cells), and the large-scale production in PRC.
Metal components ("Hardware - BOS" in this graph) did get cheaper in the same time frame ($0.6 per watt to $0.5 per watt),
but their cost cannot be reduced as much exactly because they are just a piece of metal i.e. there is no low-hanging fruit in Metallurgy.
I think this graph sheds some light on your question:
https://www.nrel.gov/solar/market-research-analysis/solar-in...
What happened in the last decade was that solar panels ("Module" in this graph) got very very cheap. They used to cost $3 per watt in 2010, but now only cost $0.3 per watt.
This extreme price drop happened thanks to technical innovations (such as commoditization of PERC cells), and the large-scale production in PRC.
Metal components ("Hardware - BOS" in this graph) did get cheaper in the same time frame ($0.6 per watt to $0.5 per watt), but their cost cannot be reduced as much exactly because they are just a piece of metal i.e. there is no low-hanging fruit in Metallurgy.