There's already case law on these sorts of shenanigans: Midler v. Ford Motor Co., so Altman was either ignorant of this, in which case OpenAI needs new counsel, or he knew and did it anyway, because fuck you Scarlett Johannson. I'm pretty sure it's the latter.

https://gizmodo.com/openai-pausing-chatgpt-4o-scarlett-johansson-voice-1851488261

OpenAI Will Ditch ChatGPT's Scarlett Johansson-Like Voice: Report

ChatGPT-4o's "Sky" voice belongs to a different actress and is not meant to be an imitation, OpenAI said

Gizmodo
@scalzi Johannson is famous but with 8 billion of us on this planet, is it even POSSIBLE to synthesize a voice that sounds human [desired feature] but does not sound like any one person [apparently NOT desired]?
@ottomate @scalzi It should be relatively easy to synthesize a voice that doesn't sound like the celebrity that they were in failed negotiations with to use their voice rights, who also voiced an AI in a well-known film. With anyone else they would have had plausible deniability.