I think you are drastically underestimating the amount of necessary work required to keep our civilization running. It's not just a matter of producing necessities--food, clothing, and shelter. The tools needed for people to "realize their potential" take work too. For example, the medium through which we are having this conversation, which is the most potent tool ever invented to help people realize their potential, took a lot of work to build and takes a lot of work to maintain.

Easy answer, the narrative embedded into our worldview (and in the worldview of many if not most decision makers) is that without work and the kind of structure it brings, people cannot be functional members of society. It plays itself out both externally and internally.

I’m reminded of Ursula Le Guin: “We live in capitalism, its power seems inescapable – but then, so did the divine right of kings. Any human power can be resisted and changed by human beings.“

>The global economy already produces enough for every man, woman and child.

But does it produce enough for every man, woman and child in a sustainable manner, and will it be able to keep up with the Malthusian population growth that would continue unabated if every person on earth was perpetually guaranteed to get "enough"?

The answer to both of those is no. While there is certainly a lot of inefficient busy work amongst the workforce of developed nations, to say that most people on earth waste their lives doing unnecessary work is an extraordinarily myopic claim that's been bandied about since that one guy wrote an article about BS jobs. Everyone latches onto that meme and assumes the majority of work being done is absolutely worthless, but they really have nothing to back that up except their own personal experience as a middle class corporate drone.

Malthus was wrong: access to birth control correlates with wealth

Malthus was temporarily wrong at best. You are taking an extremely narrow slice of human history and extrapolating the future from it. Without a controlling global enforcement of birth control (none currently exists and undoubtedly won't any time soon), then those who don't use birth control (whether driven through cultural or biological means) will have more fecundity and quickly outbreed and replace those that do. And if everyone is guaranteed equal sustenance and resources it will very quickly devolve into a Malthusian situation.

tl;dr Give everyone and their offspring guaranteed sustenance and the Catholics and Nigerians will take over in a couple generation. Nothing about the OPs post said give everyone enough wealth and force birth control so that they only reproduce at a replacement rate.

Not if the LDS Church has anything to say about it. I can't speak to the fecundity of the modern Nigerian family, but I'd wager the average American Catholic family is smaller than the average American LDS family , and by significant margin. Anecdotally, a former colleague (an LDS member) recently welcomed his 11th child. Apparently, a family with 11 kids was neither extreme nor unusual in his ward.

Hah, yea I was just going with Catholics since they've been burned into the collective conscious as anti-birth control. Seems most of them don't actually listen to the Pope much these days.

this is the same as the argument that gay people will die out because they don't reproduce