[lobe]

Couldn't the consumer deduce that the better ROI is to keep the money as cash (or some other liquid investment) for 2-3 years and then spend it on solar in 2 years time? My expectation of future prices definitely affects how I spend my money today.

[marcosdumay]

Yes, there are possibilities for speculating, but you are betting prices will fall faster than inflation + the ROI of your investment.

Plenty of people don't want that kind of risk.