With how bad Opus 5 and how expensive and limited Fable is, I would not be surprised.

Are there any figure to back up people moving to Codex?

I’ve been using both at the same time, but fable had me hitting my limits; even less will have me get 2x codex max instead of one of each.

I think the better comparison point is Opus 5. I'm also using both and I think overall I like Opus slightly better, but I'm still using Codex a lot for any project requiring image handling.

I moved a while back when Claude started refusing to do security audits and also failed to run properly in my sandbox without a lot of wrangling. Renamed Claude.md to agents.md and had no problems at all. There’s almost 0 switching cost.

No. Here's a data point: I tried it for a few days. While it worked fine I didn't see any benefit to switching since it costs the same ($100) and I've spent a year getting up to speed on Claude usage and quirks.

I for one, and I know of plenty others.