The Myth of the Master Bath

I grew up in a lovely middle class home without a master bath.  My husband grew up in a lovely middle class home without a master bath.  Our children grew up in a lovely middle class home without a master bath.  None of us seem to have needed dialectical behavioral therapy to get over the trauma incurred.  

Yet, the belief today is that if you sell your well-situated beautiful home without a large bathroom that can be entered only through the master bedroom, you are dooming the buyer to a massively expensive remodel because the situation is intolerable.  Indeed, the current standard is that there is one bathroom for every bedroom, preferably accessible only through that bedroom.  This is received wisdom in the world of real estate.

Will someone please tell me when, why and how did this become an American norm?

Am I alone in not only not needing a master bath but actually not preferring one?  My husband and I, who don't have a master bath at home, just spent a week in a vacation home with one.  Every night, if we needed to get up and use the bathroom, we left the bedroom and headed to the nearest other bathroom.  Why?  It is loud to have someone using a bathroom right off the bedroom.  It seems more considerate to take our business elsewhere.

Likewise, while I did find it crucial to have more than one bathroom in raising children, I find it wasteful and perhaps dangerous for each child to have their own baths.  Too much privacy can be a dangerous thing for teenagers.  And a sibling pounding on the bathroom door is a good check on over elaborate beauty preparations.

That is all.