"Today the average price of an original (but modernized) E. P. Janes home is around $1 million, even with only one bathroom due to the small footprint."
$1M 1-bathroom home? Just another day that ends in Y in CA.
Multiple bathrooms in houses is a relatively modern thing. And it's the sort of thing that's often hard to retrofit. So houses that are otherwise desirable may otherwise be short of bathrooms by modern standards.
At the peak of construction, Levitt was building one house every 16 minutes. Each house cost around $8,000, a price that was reduced to about $400 with GI bill benefits
https://en.wikipedia.org/wiki/Levittown
Soldiers coming back after WW2 could get a house for 400$. And it had 2 bathrooms
African American GIs, who served with honor in World War II, could work on Levittown construction crews but could not join the hordes of people pressing into Levittown rental and sales offices.
This was very much the root of one of the great economic divisons in modern US times .. the post WWII boom and generational multiplying effects were segregated.
My grandfather was a WWII, Korea, and Vietnam vet with the GI Bill. In 1968, there was no housing discount, only low interest loans. Their house cost $10k then and sold for $2.1m in 2018. I have the original copies of the deeds and of their loan.