This headline (and article) is IMHO promoting a unit-less metric.

There's no mention of the yield in quality improvement per hour of simulation. I.e., how much better does the vehicle drive using the learnings from these 876,000 sim hours?

Once a sim pipeline is set up, it's "easy" to scale up the number of hours it runs (throw it more compute resources, throw it more scenarios). But that doesn't mean the analysis scales up, or the quality of the sim results, or the application of analysis to bug fixes or feature development.