Actually, the Chinese have been doing this for centuries. At least up until the 1980s (don't know about now) they didn't use diapers. They dressed their children in "split pants" -- no seam up the back.
Easy to pop the baby onto the proper receptacle at the proper time, and when they were toddlers, easy for the child to learn to squat at the appropriate time.
I agree that it sounds like a challenge that modern American mothers couldn't handle. However, I have noticed that children are toilet trained later and later, now that Americans are using disposable diapers that "wick" the moisture away from the child's bottom instead of cloth diapers. The kid doesn't KNOW when he/she is wet.
Recently they have developed a product that keeps the moisture where it is deposited to signal the child to combat this problem.
It is no "challenge" to let a baby run your life around his/her bodily functions.
There are still barbaric cultures where the adults squat whenever and wherever they please.
I guess some countries other than the USA would call this "enlightened"..I call it lazy, dirty, and disgusting.
China is also the world's largest petri dish and the chief exporter of wonderful products like SARS, influenza, and dozens of diseases that emerge from unsanitary conditions.