The "People" section on the right on their github organization[0] shows members of the core team. It's also free software and surrounded by a passionate community, so it's pretty hard that it would die out. Andrew is irreplaceable though.
As a software engineering lead I am becoming more replaceable every year as others learn to maintain various components of the project. Recently, I am proud to have dropped to having fewer than 50% of total commits in the Git repository for the compiler.