They'd be relatively expensive because they require more labor to install, and these days labor is the biggest cost. Older homes had better craftsmanship because labor was much cheaper back then, even highly skilled labor.
Engineered, cookie-cutter building materials are a substitute for labor. They're also a substitute for the fact that high-quality, old-growth lumber is gone, so if you want dimensional stability and moisture resistance you have to rely on engineered solutions.
I have 90-year-old sash windows in my house. I think they're great aesthetically and mechanically but previous owners didn't properly maintain them (because labor is expensive!) so they're nearing their useful life. Equivalent replacements will be quiet expensive, not to mention the labor to make sure they're installed properly, modern or not.
The frames are built from really thick wooden beams that can take a beating. I had a large tree fall on my house earlier this year, and the trunk bounced/slid off, doing only superficial damage to the roof and siding; I talked to multiple contractors and insurance people who said a newer house built using modern construction standards would've been flattened, or at least suffered serious structural damage.
Things like windows are built to last too. The original wooden sash cord designs are still functioning 100+ years after they were built, with the exception of a couple windows that needed the cords replaced, but that's relatively cheap and easy. I expect the same windows will continue to work another 100 years as long as they're cared for and maintained.
This isn't about "the democratization of luxury", as another commenter suggested. Cheap construction costs more in the long term. This is about a cultural shift toward favoring short-term over long-term thinking. Long-lasting wood sash cord windows would not be expensive to build in this day and age, and they could be quite energy efficient too with modern glass and weather stripping, but people don't think or care about the long term the way they used to, and so they'd would rather settle for cheap, shiny vinyl windows that yellow and crack and fall apart in a matter of decades.