The Enduring Three Stooges

Moe, Larry, and Curly (forget Shemp, Joe Besser, Curly Joe) made movies between 1934 and 1946 and still are popular today. Almost anywhere in the country a TV station is running Three Stooges short movies. A song called "The Curly Shuffle" was made in 1983. Sam in the TV series Cheers frequently referred to the Three Stooges. MASH had an episode in which three Korean doctors were referred to as Moe, Larry, and Curly. A movie was made in 2012 and one is scheduled to begin production in 2018. Why is there such an enduring affection for these three characters more than seven decades after Moe, Larry, and Curly made their last short movie?