keep in mind fable = mythos which as been "done" since february. so the gap is not 2 months, it's more like - techniques probably started "working" in late 2025, now are trickling down to 2nd tier labs 9 months later.

Maybe because frontier labs buy the same RL tasks from task producer companies.

Yes it does, it just means all the companies come out with similar models around the same time. If what they were doing was completely novel, it would take a long time to repeat. As it is now each company releases a new model every few months, and every couple years the "leading" company changes.