Its simply not going to happen. People like Nadella call it 'tacit knowledge' - the reality is the work people do is much broader than what is producible by LLMs alone. Without the human, there is no work done. Unlike classic machinery, LLMs are not comparable in that you cant simply reduce labour input by X and be fine. Sure in the short term the consequences will not show up, but in the long term they will.
Altman and co. get down on their knees and pray that proposition is only transitory in the short run.
LLMs wont disappear, but they wont be large profit generators either. Especially not so whilst there is fierce competition and every dollar of profit is re-invested. The value of an asset is derived upon its potential cash return, net of reinvestment, taxes et al.
Altman is hoping to survive long enough to finance R&D to figure out how to encode the entirety of what humans do, to be able to come good on the asinine aspirations he has put forth that justify its valuation. But it will end in disaster.
Of course there will be humans, just way less of them.
Instead of ten, you just need two or three