Cares were owed by the masses by 1927 as that was the end date of production of the Model T Ford. There were plenty of manufacturers around by then. Also driving licenses were around from 1903 and tests became mandatory in 1934. My Grandfather already had a car by that point so never took a test. So cars were common place, though possibly not as much as now. So house designs would have included cars. By the date that Le Corbusier designed the house cars were common.

I do agree that homes should be built with flood resistance in mind, but that would hit builders profit margins, and with homes already very expensive, most buyers could not afford them if they were included.

There would undoubtedly be a cost for making more flood resistant properties but if the required features were fairly standard then economies of scale would bring costs down rather rapidly. No house builder is likely to include such features on a whim unless they are being paid directly by the customer to include them so it would require changes to building regulations to make a minimum level of flood proofing mandatory in the same way that things like insulation are now.

Yep, complete with helipad on the roof for those essential Tesco grocery deliveries.

Building a home is rather cheap, it's the land cost that's the problem.

Where I live, the land is about a third of the total cost of building a new house (average family house). We looked into it, when we bought our house. But finding a decent plot of land in a good position was difficult, so we ended up buying an old house. That said, what we saved over building new, we have spent on renovating the old house...