I'm surprised no one at Google realized that both OpenAI and Anthropic's naming schemes follow a fairly clear progression and that they should do something similar to reduce confusion. I would have assumed the opposite given that Argon has a higher periodic number

Both seem to have the same pricing: $2 in / $10 out initially, rising to $4 in / $20 out after the introductory period. That made me wonder whether Carbon might be Argon with additional RL training. What’s the Opus/Sonnet comparison based on?

I don't think that's right. Carbon and Argon have the same price.

I suspect they're using a new naming convention because they had previous contractual obligations tied to the "pro" and "flash" naming, and by switching to a new naming schema they avoid those commitments.

No, it's not. The naming is just bad. It's the next iteration of Argon

Carbon is Fable / Astra level. Argon is their Opus / Sol.

Helium will be small and squeaky I presume

So Argon was 4.0 Flash effectively? Interesting that there is such a small gap between their new Pro and Flash tiers