Probably the same reason a Epyc 9965 from hetzner performs just as well as one from AWS for one tenth the cost.
Anthropic is offering a commodity product and trying to convince you it isn’t.
It’s even in the name, it’s a myth and a fable. Never happened doesn’t exist.
Also I believe at least on coding that qwen is now the frontier model, fable is its copy of frontier models. In the same way that the Ferrari Luce is an expensive imitation of a SU7 Ultra.