I think he hit the primary reason in this paragraph from the article: We might need hundreds of hours of CPU time for a simulation, then nothing while we figur

I think he hit the primary reason in this paragraph from the article: We might need hundreds of hours of CPU time for a simulation, then nothing while we figure out what to do next, then another hundreds hours to run a modification. Now that CPU time is so readily available vs. the mainframe era or even just the pre-cloud era, there's far less capacity-forced "figure out what to do next" time unless you've got an extremely computationally heavy problem or are very resource-constrained. As such, there's a lot less unmet demand for compute out in the world, which naturally brings cost down.