Mainly cost. Right now a GaN mosfet costs 10x more than a silicon one of similar power rating. You are starting to see them in consumer goods where they can re

Mainly cost. Right now a GaN mosfet costs 10x more than a silicon one of similar power rating. You are starting to see them in consumer goods where they can reduce the total system cost, or get the size down in premium goods. For higher power stuff, they have to compete with silicon carbide which can handle very high temperatures, so your cooling needs are smaller. [0]: IPAW60R380CEXKSA1 (silicon) costs $1.27, IGT60R190D1SATMA1 (GaN) costs $13.