It wasn't just spiraling costs, but also the collapse in the steady 7%/year growth in electrical energy demand. Without transparency on demand growth, very long term investments become risky (a risk reflected in the bankruptcy of WPPSS). The passage of PURPA in 1978 also didn't help with this as it allowed a flood of non-utility generation onto the grid, helping soak up what demand growth there was.

Yes, regulations started tightening before TMI.

> This ”before regulations” time period seems to be made up on feelings about a rosy picture of the past rather than actual data.

No, we have data about costs in those earlier times, and we know what regulations came in when.

Given the cleanup costs of the early nuclear program maybe they learned a thing or two preventing the externalization of costs?

DOE report: Cost to finish cleaning up Hanford site could exceed $589 billion

https://www.ans.org/news/2025-04-17/article-6942/doe-report-...

Sellafield cleanup cost rises to £136bn amid tensions with Treasury

https://www.theguardian.com/business/2024/oct/23/sellafield-...