There’s some debate as to how much use was made of curtains (vela) vs solid doors.
The Straight Road still exists.
Modern suburban building regulations usually demand a 8 to 10 foot separation or 6 feet setback from the property line. As mentioned, the Roman style was more intended for denser cities where space was at a premium, since due to lack of cars, people tended to walk around town.
Also, we have the tools and materials (cheap nails, power saws, for example) to build two stories or more and make it quite comfortable. IIRC, Roman partment buildings tended to be stacked arches -stonework was not cheap, likely not worth it for a simple dwelling except maybe attic storage.
I live in something very similar and it is indeed pretty desirable (to me). Mine is U shaped, so not completely enclosed. You enter the front door into an outdoor courtyard with a rectangular 20x30 foot pool, and there are four sets of french doors that open into various parts of the house from this courtyard (We mostly only use two of them, as you can get to all parts of the house easily enough through them, but on a cool, breezy day, we do open them all up). There is about a 10 foot overhang of the roof that covers the patio surrounding the pool area. There is nothing Roman looking about the architecture, but the basic layout suits me wonderfully.
Exactly, this is a feature, not a bug, at least in a Mediterranean environment. Those courtyards are surrounded by deep roof overhangs and/or colonnades to provide as much shade as possible to the rooms surrounding it. The small pool or fountain in the middle, as well as some plants, provide enough evaporative cooling to lower the temperature even more. If you’re careful which windows you open in the home then the wind can flush out the stale air in the morning, or keep the cool bubble of air in during the day. The courtyard is also something pretty to look at and a pleasant place to be versus looking at your neighbor’s blank wall or being right next to your other neighbor’s latrine. This sort of courtyard house is a decidedly urban typology.
Zillow Gone Wild lists an unfinished villa in Indiana for $1,500,000. I would describe it as “just past in the dry.”