We learned much from this fine article. I bought a 640 in 1990 and carried it for years as a Deputy. It is as perfect a gun for it's use as ever designed.
Historically, S&W was years behind Colt in the concealable 38 Special department. While S&W made their 38 Specials bigger and bigger, Colt developed the Police Positive Special and offered the 2" version in 1927, thus becoming the Detective Special. The DS was the first real snubnosed 38 Special and was hugely popular.
Of course, S&W developed the Chief Special and followed up by introducing the MANY options throughout the years, as detailed in your fine article. Most S&W snubs are still available and more popular than ever with a new "Bodyguard" now out in plastic. Colts have been out of production for years.