Andrew Pears was a barber in SOHO London and his clients included wealthy socialites who were particular about their appearance. They had the same obsession with fair skin as the Indians have currently and tanned complexion was associated with the workers and blue collar people, you know the kind that does manual labor outdoors. In the absence of "Fair-n-Lovely" and other fairness creams, and other fairness products, people obsessed with a fairer complexion used powders and creams by Pears to cover up spots and damage caused by the lead contaning and harsh beauty products, not unlike men using "Cuticura talc" to look a shade lighter.
Mr. Pears realized that beauty products are a far more profitable business than cutting hair and this gave birth to Pears soap. Pears started experimenting with soap purification and the end result of that was a glycerine soap. I am sure having a translucent soap had its advantages as it must have been easier to market.
This is how Pears Glycerine Soap was made and to this day that have the first mover advantage. There can be a hundred soaps better and gentler than Pears but none of them can displace Pears Soap from the mind of a mother when she is choosing a gentle soap for her new born.