According to the article, the word After here is incorrect. It states the voice actor was hired months before the first contact with SJ. They might be lying, but when they hired the voice actor seems like it would be a verifiable fact that has contracts and other documentation.
And like others, not defending OpenAI, but that timeline does tend to break the narrative you put forth in this post.
He probably just really wants to actually have SJ's voice from the film. But SJ doesn't really have a right to arbitrary west coast vocal fry female voices. Without the "disembodied voice of an AI" element, I don't think most people would note "Oh she sounds like SJ". In fact, that's what the voice actress herself has said -- she hadn't gotten compared to SJ before this.
First of all, if you read TFA, you would see that the voice actress was hired before ScarJo was ever contacted.
Second of all, just because Altman contacts ScarJo it does not necessarily have anything to do with the voice of Sky. He may well have wanted to add ScarJo as an additional voice.
Third of all, whether the voices sound "just like" each other is clearly debatable. Once again you're locking in on the least favorable interpretation possible.
How about this for a "narrative":
OpenAI start a hiring process to create a diverse set of voices for their product. One of the voices happens to sound ever so slightly like Scarlett Johansson. Sam Altman is completely unaware of this, despite the fact that he really likes the movie "Her". He's just not that involved in the hiring process.
He recognizes that their product is obviously similar to the movie, not in terms of the voice itself, but in terms of its capabilities and operation. He thinks it would be funny to get the actual voice actress from the movie. He reaches out to ScarJo, she says no. Some months pass by, and as they are about to release, he thinks again "damn, we got a great product here, let me check again if she would be interested in voicing it".
Then they launch, and Altman thinks that even though they didn't manage to get Scarlett Johansson's voice, the product is still clearly reminiscent of the movie "Her", just because of what it does. He tweets "her" because it's still more than close enough, not because of the voice, but just because of how the product works.
The public, realizing that the product is indeed really similar to the movie, and hearing the voice that just so happened to be ever so slightly similar to Scarlett Johansson, interpret it as if the voice was somehow meant to be a clone, when it's really just the context that makes it seem like it could be similar at all. Altman didn't get the voice he wanted, and Sky was just happenstance.
Now I'm not saying this is how it went down, but you keep pointing fingers acting like you know exactly who did what and all the reasons they did it for.
After "she" said no, then Altman auditions a bunch of voice talent and picks someone who sounds just like SJ. I guess that's just the kind of voice he likes.
So, Altman has forgotten about SJ, has 5 voice talents in the bag, and is good to go, right? But then, 2 days(!) before the release he calls SJ again, asking her to reconsider (getting nervous about what he's about to release, perhaps?).
But still, maybe we should give Altman the benefit of the doubt, and assume he wanted SJ so badly because he had a crush on her or something?
Then on release day, Altman tweets "her", and reveals a demo not of a sober AI assistant with a voice interface, but of a cringe-inducing AI girlfriend trying to be flirty and emotional. He could have picked any of the five voices for the demo, but you know ...
But as you say, he's not admitting anything. When he tweeted "her" maybe it was because he saw the movie for the first time the night before?