Momentum from Claude Code's success at the start of the year and hype from Fable I think. It seems like most people I know have switched back to GPT-5.6 (which I find gives much results than Fable, you get more usage), but I imagine that will take some time to fan out.

if this is true, openAI is truly done.

Now they're slashing prices across the board in a desperate bid to show some kind of growth, if not revenue.