It's not silly. The computer that could beat Kasparov couldn't do anything else so of course it wasn't Artificial General Intelligence.
o3 can do much much more. There is nothing narrow about SOTA LLMs. They are already General. It doesn't matter what ARC Maintainers have said. There is no common definition of General that LLMs fail to meet. It's not a binary thing.
By the time a single machine covers every little test humanity can devise, what comes out of that is not 'AGI' as the words themselves mean but a General Super Intelligence.