You may want to do a quick search on what write amplification means. It's an undesirable property of data structures.

I think you perhaps meant fan out, which is partially valid but addressed in the submitted article - i.e. bus speeds have improved greatly. In fact to the point where you can easily have no bus at all: point to point PCIe lanes to each NVMe device.

A zmirror is simple too, and gives you boot environments so you can roll back failed upgrades and other magic.