You can get a new home built in Georgian Revival style but it’s going to be expensive. Home builders rely on easy to source, mass produced, standard parts. In my experience the cost goes way up. For instance, a truss can’t be used for the roof and windows are custom, etc. and there’s going to be a lot of windows.
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.
I dunno, I'm not a stickler for details. For example, I know that windows with many small panes ("muntins") are not cost-effective today and partially defeat the benefits of double and triple glazing, and the alternatives (fake bars that are glued on or between the glass) look shockingly bad... but any kind of partition at all (casement, fixed pane + tilt-turn pane, etc.) already adds visual interest and does not look out of place, as e.g. is evident in this photo of Georgian architecture with windows that I'm guessing are not historically accurate: https://upload.wikimedia.org/wikipedia/commons/7/78/Baggot_S...
My home has muntins, and I have to say they are incredibly convenient. If a ball goes through a window or something, it's extremely easy to replace; and very cheap. Highly recommend.
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.
Nowadays the window that was broken would just be replaced. Luckily they pop out easily!
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.
I think some of the higher-end window grills (a "stuck on the outside muntin" for a short-hand description) look fine from any distance that they're typically seen.
Having a higher end window where the mutton/grill is dominated on both sides is best imo. It looks awful from the outside when it’s an interior stick-on as there’s no dimension and line you mentioned lack of shadow lines. You generally have to go to the higher end though, like a Marvin Ultimate. 30 of those on a house, installed, just set you back $60k+. But they look great.
I had windows like those. The glued cross shaped frame was not actually glued and it was on both sides. It looked beautiful but it was a nightmare to clean. Four small glasses instead of a large one. It was wood, single layer glass. I replaced them with something that reduced the heat flow.
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.