Yes, though is suspect it is cultural. A team that writes slow flakey tests probably writes slow flakey production code too, for the same reasons.

I'm sure that's a factor, but having slow tests makes it much harder to notice when you have made the actual code slower.

A team that insists on high-performance tests probably ships lots of bugs, because the tests are so local/isolated/mock-driven that they don’t actually exercise interesting interactions.