There have been enormous strides here. We have developed WebAssembly and WIT, with Extism as a chrome over then providing tower of babel between most programming language pairs. We have GraalVM and Truffle to unify languages under one compiler. We have LLVM bitcode to combine languages targeting native machine code for many architectures directly. Swift, Zig, Jai all implement C interop on their own terms. AI agents allow us to re-target algorithms between languages with no compiler interoperability. There are countless pretty darn good ways for programs to communicate through message passing - MachO XPC, Dbus, COM, gRPC, HTTP3 (+ , ZeroMQ, Fuchsia Zircon+FIDL, unix domain sockets. There are more programmers now than at any time in history.
Yes these can be used as alternatives sometimes, but they are not really the same thing. We need a streamlined way for reusable libraries (written in different languages) to be consumed by different languages while not being limited to a specific runtime or platform. When code from different languages needs to be able to run inside the same process, with low calling overhead and avoiding copying when possible.
Your answer just throws in anything that enables programs to communicate somehow, ignoring all the differences and tradeoffs to what is being discussed here. Many of your solutions lock you in to a specific platform, a language or add a non-trivial overhead like message serialization or add an unnecessary complexity to a program. Also, IR does not solve the same problem as ABI.
im just pointing out (a) a ton of work has gone into this, (b) yielding many options for different use-cases, (c) without dependency on c-abi/c-header.