Having single toilet is adequate for most small families who can easily stagger toilet usage in the morning rush hour. Singles, couples, retired folks, rural folks, people who do not have to use toilets all at once to get ready for job commute in the morning would have no need or excuse to take desperate measures. That is normal. But we are not talking ‘normal’.
When shit happens, it happens, it can not wait and it does not need ‘excuse’. Either its in the toilet or it is in the pants or somewhere else. And London row houses does create situations that are not ‘normal’
In USA, size of families tend to be smaller, with sizable population consisting of singles, single parents, retired folks and couples with no children. There is also sizable population who does not have to get ready in the morning or go out to work in the morning. For them, having only 1 toilet is never an issue. Most 2-3 bedroom apartments/houses have more than one toilets anyway. Most landlords also rent 1 bedroom/toilet apartments only to smaller families. Plus, America has invested heavily in creating ample public toilet/restroom facilities and created building codes to mandate toilets in all public places, which mitigate any need or excuse to go out in public.
Get real, in America homes were built with a single bathroom during the big family era, the post war years and the pre-war years, decades and generations of building homes with a single bath, many if not most of us grew up in them, countless millions live with them today.
The luxury of having two bathrooms is a fairly recent situation, most boomers didn’t have 2 when they started life, in fact in 1960 17% of US homes didn’t ANY indoor toilet or bathroom, yet we still never heard of, nor experienced public defecation.
Your description of hand ringing helplessness in an effort to tell us that Americans are, or were having to defecate in public because big sister was putting on her makeup, is silly.
I have lived in those houses and apartments all over the US, they are everywhere, entire neighborhoods of them.
You are spewing nonsense to justify a ridiculous image of British and American dads going out and defecating in the open because their teen son is showering for too long, or because mom is blow drying her hair.
What you are describing is 3rd world immigrants.