The problem is that it'd require a lot more effort than that. Not only do you need the two people, you need the content teams to make sure users who are hacked can find information about how to contact the right people, you need devs to build tools for the two people to investigate and "unhack" compromised accounts, you need processes to make sure attackers can't compromise an account by falsely claiming its been hacked, and then you need all the usual things around managing those two people like HR, line management, review, hiring, etc.

Adding people to an org, even one as big as Meta, is never a simple process.