R&D and tooling costs have grown enormously to bring new fab process nodes online, but the actual per-wafer costs of materials and operating expenses historically haven't been growing to the same alarming degree. But that's changing, as new nodes are increasingly relying on power-hungry tools with low throughput that wear out mask sets at an unprecedented rate. It's not implausible for the industry to reach a point where new leading-edge processes will never mature to the point that they make economic sense for the low-cost applications that currently stay a few nodes behind the leading edge.