Houses aren't nearly that far along yet.
And ownerless taxis don't need to be non-greedy. The algorithms that make the most money and are able to produce the most offspring (either by buying other cars or paying off a factory to build more) will probably help the economy the most. If the car is effective at making money, 1 car can eventually turn into 1000 with little human management. A non-greedy car might not be able to achieve that.
Several authors have written about algorithmically generated & operated companies or entities (Charlie Stross, the Ghost in the Shell) either as litigation shields or entities which outlived their owners but continued to operate.
The idea is certainly odd, to essentially create autonomous and roughly speaking self-sufficient/directed artificial creatures, but it's consistent at least.
The thought that makes me saddest i think is just that the core quality we'd imbue humanity's first autonomous creations with would be capitalist wage-slavery (a literal non-hyperbolic one in this case).
By what and who's metric? There is no stable, verifiable entity "society as a whole".
This system of wage-slavery is enforced today through police, lawyers, bankers and politicians working in accidental concert to ensure that you must go into debt (by renting or buying a house), and that you must work for whatever wages you can attract (because no money means no place to live), or be thrown in gaol for the sin of being poor.
There are towns in the USA re-introducing debtors prisons ("poor houses") where people who have defaulted on debt repayments can live in penury, having their wages garnished by the state before they get hold of the money themselves.
You mig have other rationalisations for it.
The ultimate absentee landlord?
Are you intentionally changing the subject, or do you equate self ownership to "ownerless"? Or is it that you are skipping ahead logically because you don't recognize a non-human entity as being capable of self ownership? If that is the case, that is the more important issue that needs to be discussed.
If you think driverless taxis are such a great idea and you want them to be operated in a non-greedy way, start a non-profit, or start a corporation and make it public so that anyone who wants can invest and share in the profits, and pay dividends. If you insist "nobody" owns and operates the fleet of cars, it will probably end up being the government, who already programs the fare boxes in taxis.