The vast majority of humanity would disagree with you. And in fact, this is how the vast majority of humans live today.
"humans are left to nibble at the margins and dance to the tune of their betters." Isn't that society today, but without the wealth of Culture society?
Indeed, to the degree that the Culture represents an aspirational fantasy, it is not "what if society were dominated and controlled by vastly powerful machines", because that is the world we already live in, but "wouldn't it be nice if the vastly powerful machines which dominate our lives liked us and cared about our well-being?"
"humans are left to nibble at the margins and dance to the tune of their betters." Isn't that society today, but without the wealth of Culture society?