Yes. It seems logical that there have been some licensing negotiations that we're not aware of, and maybe all this is part of ongoing negotiations too.

What's puzzling is that they're keeping il2cpp closed. Opening it would make sense and would show they mean serious business but keeping it closed makes me wonder if their risk will pay off or if it's just a bluff.

However, unlike PHP which is dynamic, C# is statically typed. It is a much more direct match for C++, and performance should be pretty good.

But with that said, I think your point still stands, as there are still things like bounds checks in C# which would need to remain when compiled to C++, while idiomatic C# might not have those checks.

I wonder though if those bounds checks couldn't be disabled in some cases. Sandboxing isn't a concern on the Unity WebGL port, for example, since the browser provides that, so il2cpp code doesn't need to be safe in that sense.