Current production seems very counterintuitive from a manufacturing/industrial engineering perspective. There are around 9 main processes and only about 3 add material. Depending on the chip design, it's probably going to 500-2000 manufacturing steps. That being said, each silicon wafer can hold up to hundreds of chips, making for a big batch. Going up to 18" wafers would make it even more appealing to stick with current methods of production.

With how expensive all fab machines are, I don't see it becoming economical anytime soon for a complete overhaul of tooling.