In USA 3% of the population work in agriculture and they produce enough to export. So I say it's enough for 10% to work and 90% to do whatever they want. Houses do not need to be built all the time, food and clothes I do not think will be a problem. If a nation would set it as a goal I am sure that within 1 year they would have enough clothing and housing for a very long time.
What will people do ? Whatever they want, I told you, if you want more than what is provided create it yourself, associate with others and do it. Nobody forces you to eat and wear only what is provided. About houses, problem can be solved, build many of them to allow people to move wherever they want. I am sure there are lots of young people starting their career wanting to save the world , then realising that all they do is helping some rich person getting richer, and there is nobody to save, is each man for himself. I would gladly work for free if there is a need ( not economic need of money), if I knew I had food and shelter taken care of. Even beyond my proposed 10 year work period.
To prevent that system from becoming what we have today no money will be allowed. No banks no nothing. This system of mine has the purpose of protecting the planet and the people from their own greed.
It all started when a fisherman understood he can fish more than he can eat, because he exchanged the fish for money. Soon he owned a fishing fleet and eradicated the fish. What about the others from his village ? Who cares, they had to get jobs somewhere, lazy people !
We have this stupid concept that people cannot just "live" they have to work ! I mean "if I suffer why don't they suffer !"
See the book "Ishmael" by Daniel Quinn, who wants a pdf version of it I can send it trough email.
If people see helping others as a thing that is valued in society they will do it. If people see getting more money and stuff as a valued thing, each man for himself, and who cares about the planet, we only live for a short time, they will do that