Perhaps FAANG pays so much exactly because of this? I mean, they want the best of the best because maintaining patchy code (without breaking production) is difficult and painful. At least, in my experience in non-FAANG companies: they pay the big bucks to do the difficult stuff (e.g., maintain legacy patchy code without breaking production and bringing money to the company) not for doing the easy stuff (e.g., starting from scratch some cute microservice using DDD and Hexagonal Architecture).