Much too simple.

Most "risks" have an upside and a downside. In this case, for example, the solar PV system may be working better or worse than the (potential) buyer initially comes to understand.

We have huge industries based on selling "risk, but with a huge potential upside" to people willing to pay for access to the potential upside. Many of those customers are not interested in low risk in that context.

So "more risk, pay less" is not a hard and fast rule, but depends on what is being purchased, the circumstances of the buyer, and more.