Welcome to the site, Shemoeley Fine.
I don't think Abbott and Costello are necessarily held in "higher esteem" than the Stooges except in the sense that feature films are considered "more important" than short subjects. (Unfortunately.)
All comedians have borrowed from others since time immemorial; it's the nature of the business. The Stooges routines owe a lot to their predecessors and contemporaries, such as Laurel and Hardy, Charlie Chaplin, and others. It's not so much where the routine or material came from, as how well a particular performer presents it. Lou Costello deserves his acclaim every bit as much as Curly, Moe, Larry or Shemp; he was a very funny guy, and his timing was impeccable
I've got to admit, I've always wished for a film or short with all three Howard brothers, myself, but you can't leave out Larry! He was like an adopted brother, and it just wouldn't be the same without him.