It seems to me that given how AI is likely to continuously increase capitalism's efficiency, your argument actually supports the claim you're trying to dispute.
Capitalism is not efficient, it's grabby. Read Bullshit Jobs. Moreover, capitalism isn't interested in efficiency, it's interested in grabbing more stuff. It's relatively effiicient at centralising power and resources into the pockets of shareholders, but that's probably not what you meant.
I think this is borne out even moreso in recent years, as environmental degradation continues, and we watch as capitalist systems are unable to do anything but continue to efficiently funnel money into the pockets of shareholders.
The word "efficient" can only plausibly be applied to overly simplified models in fantastical economic theories which don't reflect reality.
The kind of AI offered by companies like OpenAI may very well be an effective tool at grabbing more stuff though, sure. Or, rather, at convincing everyone they simply must move to this new area, that they control, effectively grabbing that newly created space.
