“How does it play out in your brain?”

One of the problems with the command economies that socialist states like the USSR tried to implement was that the maths was simply too complex to make it work efficiently. This is an example of something ai could be enormously useful for. Obviously no western country is going to use ai for this, because it’s contrary to their ideological and economic systems. The use that technology is put too will follow ideology. When the Industrial Revolution happened many people imagined a utopian future where the increase in productivity would lead to humans having to work far less. But today, we still spend the majority of our lives at work, and if it wasn’t for the historical efforts of socialists and trade unionists then even the restrictions on working hours, and on children working, would not exist (there are states in the US even today that are trying to repeal child labour laws). Of course ai will have benefits in regard to medicine, farming and so on. Does that mean everyone will have access to medicine, or that the workers on farms will see any benefit? Technically that would be possible, but within the ideology of capitalism it will not occur. Homelessness, poverty and unemployment exist because they are necessary for the economic system to function, not because of a lack of resources or lack of a solution. The benefits of ai will be limited by and subsumed into the ideological system - a system designed to give power and luxury to a tiny few via enforcing deprivation on the majority.

“A truly post AGI world would not have any human labour”

Perhaps, but my point is only that benefits in production and material abundance predominantly do not flow down to the working class/average person but up into the profits of the rich. Capitalism as we know it could not continue in a world where labour is unnecessary, but without changing the relations of power, the new system that emerges will simply mirror the old one. I could envision - as one possibility - a sort of tech neo-feudalism, where a Universal Basic Income is paid in return for some kind of military or other public service. But this income will go straight into the hands of the owning class - to rent, and to various rentier schemes (you will own nothing and you will be happy”, as the WEF put it). Of course this is only one scenario, but without changing the power relations, the system of deprivation for the masses and wealth and luxury for the few will remain regardless.

“You think China lifted it's people out of poverty without capitalism”

No - I agree China used capitalism to do that. But it was a different kind of capitalism to what is used in the West - goal oriented, with a long-term vision and a materialist, Marxist outlook, which aims to use capitalism as a tool to develop productive forces and to the end of benefitting it’s citizens and ultimately transitioning to socialism. This is very different from the blind profit seeking capitalism of the West.