Mojo and FIDL aren't necessarily portable outside of their respective platforms. grpc may have unnecessary overhead when used for IPC, but it's well supported,

Mojo and FIDL aren't necessarily portable outside of their respective platforms. grpc may have unnecessary overhead when used for IPC, but it's well supported, understand, and portable. I don't claim to understand the full constraints the teams you refer to were under, but I'd like you to consider that they may have done what they thought was best.