You're asking why something brand new with a warranty will cost 4x the price of something 70-90 years old?
Yeah. Because with real-estate we know that there are three things that matter, and age isn't one of those.
Especially if current conditions dictate that
The cost of construction is up because everyone subs out their jobs so there are multiple layers of people who need to get paid. And the cheapest material is used to maximize profits up the chain.
which could easily mean that the old construction would be of overall better quality/durability.