Just a point of contention. Such a socioeconomic reality is feasible and has existed and does exist to varying degrees, particularly throughout Europe and North America. Galbraith was not speaking from a pie-in-the-sky perspective as you seem to intimate. Though, as my French friends, similar to Galbraith, have hammered into my head: The French have a slightly lower per capita income than Americans yet consume considerably more social products (public transport, free daycare, an array of other social welare benefits) that more than make up for the fewer private consumer goods they can purchase.
Galbraith was certainly not speaking from an infeasible worldview. But certain tradeoffs have to be made for that worldview to be brought about. Unfortunately, in America today we don't even have serious discussions about what those tradeoffs could be. During the healthcare debate, for example, one would hear fleeting mention of single payer plans but no real discussion of what one would look like. The Canadian healthcare system, which is virtually single payer, is just a drive to our north, yet I don't recall even fleeting explanations in major media outlets of how their system works.
What Galbraith wrote is becoming less and less the American reality not because it's infeasible, but because those wealthy people who largely control the flows of information and attitudes usually make their money from consumer goods not public ones. It seems so infeasible because Fox News and CNN and, indeed, the NY Times are for-profit organizations that could very well find their owners and top executives with less after-tax income if society were to become more egalitarian. It stands to reason that they will not lavish liberal or socialist options upon you.