Keynes was a different thing - that we could cut working hours to 15 a week rather than never have to work again. I think that would be quite possible with a drop of living standards - you could do it today by moving somewhere cheap and doing some remote work. I think it didn't happen due to human nature. We both quite like doing something useful with our time and like increasing living standards.

I inherited some money and don't need to work, but do work on stuff because I like doing it. I imagine that's what things will be like post agi.

Be careful not to conflate AGI with the current generative AI revolution. Even if it may eventually lead to AGI, it is quite a way from that and the social implications of the current and near term AI is what we are talking about. We can only imagine what this will be like post AGI, but we have some idea of what shifts happen when a technology comes along that greatly amplifies human labor.

Post-scarcity utopia was not an uncommon thing in mid-20th-century sci-fi, especially when you also include Soviet Bloc countries.