Fable / Mythos are (were?) a step change in capability. The scaling laws clearly have not gone sigmoidal yet. I recently wrote about my experience with Fable and how it represented a very substantial increase the complexity of tasks possible here, if you're interested: https://tossrock.substack.com/p/36-hours-with-fable

A lot of what you describe has been enhancements and scaling. Folks have been working on AI for 70 years. Do you count putting it into the hands of you and I a breakthrough? Otherwise self-attention would certainly count but that is nearly a decade old.