The chief reason no one makes a 14nm MCU is because the cost of designing on leading edge nodes is staggering and MCUs are a small market that doesn’t make that

The chief reason no one makes a 14nm MCU is because the cost of designing on leading edge nodes is staggering and MCUs are a small market that doesn’t make that much money. Just as importantly, the MCU often tends to have a lot of analog and RF content on it, which actually gets easier worse as the nodes shrink