Examples: https://www.irishtimes.com/life-and-style/homes-and-property... - Fake Georgian townhouses. You're still left with a four storey house, which isn't super-practical, and they look ridiculous.
https://www.pjhegarty.ie/projects/esb-head-office/ - Replacing a distinctly un-Georgian Brutalist thing which itself replaced a row of Georgian houses back in the day. Again, looks silly, but if they'd played it completely straight they'd be left with a pretty impractical office building.
These things weren’t built for mom, dad and 2.4 kids, but much larger families (6? 8 kids?) who were rich enough to have their own staff living alongside. Many were eventually subdivided into tenements and by the 20th century one street managed to fit 835 people between 15 houses.
There’s a reason well maintained Georgian houses sell for approaching €2 million euro. These new Georgian-style builds are targeting the very wealthy rather than trying to be practical city centre housing, in Ireland at least.
Which is still a good bit less than you'd expect for the square footage (that would work out to 4-500eur/sqft, which would def. be on the low end for the areas they're most found in), reflecting the awkwardness of the layout.
Of course, if you consider any building older than 100 years to be "impractical", then maybe living in the historic centre of a city isn't for you? There are plenty of modern (and soulless) places to live in the more modern fringes of the city.
And I disagree - the new ESB headquarters on Fitzwilliam St doesn't look "silly" at all - it actually looks very well to my eye from the street. Unfortunately https://maps.app.goo.gl/NL2qtasuMNM89Nqg8 doesn't have enough detail to show it but certainly the materials and brickwork is of a high quality. It doesn't aim to be pastiche or fake as you call it, but it does respect the materials and elevation of the historic streetscape.
Nothing impractical about a four story building as such. The (normally five story) Georgian terraces are normally very long and narrow, though. This makes them difficult to turn into practical housing; you're looking at either awkwardly long narrow rooms, or rooms without natural light, if you turn them into apartments (and as single unit housing they're far too big for practical purposes). They also make for awkward offices (I've worked in one, back in the day).
You could... maybe make wider faux-Georgian terraces, I suppose, but at that point you're getting into the weird-looking anyway.
Probably because a lot of folks don't understand the 'old' styles and how they work. Brent Hull specializes in restoring pre-WW2 buildings, and designing new ones that follow the design rules:
* https://www.youtube.com/@BrentHull/videos
A break-down on how a Georgian house should appear (i.e., use the Golden ratio everywhere):
* https://www.youtube.com/watch?v=J-0XJpPnlrA&t=3m11s
Has a recent playlist, "New House Old Soul", on constructing new buildings (and additions) that harness the design rules of previous styles properly:
* https://www.youtube.com/playlist?list=PLjEWB3ObiETMTGy11dF91...
It’s why many homes today are built off existing models. But you see it in higher-end homes.
Now, of course the required parts could become mass produced if there were the demand. And I agree it’s a simpler and beautiful style. But you can’t put a flat roof on them.
https://aw930cdnprdcd.azureedge.net/-/media/andersenwindows/... (There's some chance that those are even internal, which are longer lasting/easier to clean, but much less convincing owing to having all the wrong shadow lines.)
I can see a modern Georgian type thing though. Definitely nicer than so much of the garbage being built today.
As for glazing... I'm not 100% sure. I've heard there are ways to get glass panes that are better insulated. My other guess is that, had muntins continued to be popular, the market would have found something. There's nothing inherently inefficient about them.
For example, one option a local window company gave to me was to simple add some plastic covering on the inside of the window. It would not reduce the outward appearance at all, but would provide some insulation. As it is, our house is quite efficient and we don't actually have any insulation. The way they used to build houses (not open floor plan, multiple stories, etc) actually make them more pleasant to live in, in my opinion. Our only issue was that, when adding AC, the original forced air venting leads to a noticeable temperature differential due to the lack of an intake on the second floor, but we'll be fixing this soon. Plus, ceiling fans have basically eliminated the worst of the problem.
For your old windows (I have many still, mainly in the front) I recommend ensuring you have good weather stripping and that you have storm windows installed. That helps a lot. Mine are double hung sashes though so the pulley boxes are massive leaks but nothing I can do about that.
I guess I could just seal the windows shut and put insulation in the pulley boxes but they are still functional even though we rarely open them.