Not all the car space maybe, but lots if it.
You don't need parking spaces anymore. No more than 2 lanes for most roads ... that sums up very big.
There are numerous city centres in the UK which use this method. The central portion of Canterbury, Kent, is a great example.
There are significant benefits to this approach other than not having to use roads, but of course the tech isn’t there yet
An entire building is less feasible unless it is small, but it could be done using modular components
Plus I don't really want my town to sound like the set of Apocalypse Now.
This is the hypothetical that GP responded to by saying it's not realistic...so you're acting like he was the one who constructed a straw man argument when he was making a reasonable point directly relevant to what another poster said.
If there's any hysteria in this conversation it's from your unreasonable response.
This might require restoring or even constructing a jetty or small siding. Any cost is balanced against the disruption and danger of taking many large vehicles through residential areas.
In the end you still need roads. You don't get to convert all of that space into a park even if you ban cars.