Insulation used to be a ton less important—wood and gas heating were cheap, and nobody had air conditioning because it didn't exist yet.
What was more important was the layout of the house, the windows, and the ceiling heights, all being thoughtfully arranged to allow the right kinds of airflow in the right seasons.
Most modern houses in climates like seen in most of the US turn into an unbearable mold-farm of a wet oven if the AC is turned off over the Summer—they depend on AC or they start kinda decaying in place within a year, aside from being unbearable to enter on a hot day. A 1900-construction house that hasn't been updated to something like modern standards is far more comfortable to live in, in those circumstances.
(your broader point that some things in modern houses are better due to e.g. improving materials or engineering even as other things like framing have gotten worse due to worsening materials, I don't dispute, but modern house design as far as airtightness and insulation is very much a trade-off that leaves them dependent on AC in many—and, as the Earth warms, ever-more—climates, not strictly an improvement)
> wood and gas heating were cheap, and nobody had air conditioning because it didn't exist yet.
Gas heating in an old house for just one month uses more energy than all HVAC loads for a year in a similar sized new house. Where I live you must heat during that month of the pipes freeze/break so there is no getting around.
I live on the Potomac River in Virginia and am regularly shocked that the "come here" houses are what they left behind in northern Virginia and the Maryland suburbs. Houses are not designed for cross ventilation or with deep porches, and the like. I mean, all the cottages we visited on Cape Cod in my younger days were designed to have windows open and for the natural sea breeze to do the heavy lifting.
What was more important was the layout of the house, the windows, and the ceiling heights, all being thoughtfully arranged to allow the right kinds of airflow in the right seasons.
Most modern houses in climates like seen in most of the US turn into an unbearable mold-farm of a wet oven if the AC is turned off over the Summer—they depend on AC or they start kinda decaying in place within a year, aside from being unbearable to enter on a hot day. A 1900-construction house that hasn't been updated to something like modern standards is far more comfortable to live in, in those circumstances.
(your broader point that some things in modern houses are better due to e.g. improving materials or engineering even as other things like framing have gotten worse due to worsening materials, I don't dispute, but modern house design as far as airtightness and insulation is very much a trade-off that leaves them dependent on AC in many—and, as the Earth warms, ever-more—climates, not strictly an improvement)