Song Covers Pre 1950

A couple of weeks ago we listened to a short sample of "Anything Goes" written by Cole Porter but performed by someone else. The original version (performed by Cole Porter) I think is excellent, given the context of the song and Cole's almost comical voice I think it fits perfectly, although admittedly most of it makes no sense to me. This got me wondering about covers pre-1950's where means of distributing music was still in its infancy.

I wonder if covers were more prominent earlier on? I recall in the movie "Ray" we see Ray Charles get his start playing Nat King Cole before finding his own sound. Even than, "Georgia on My Mind" one of his more famous songs is a cover . Also it seems like every singer with a voice covers "Summertime" by George Gershwin (even Duke Ellington covers it). I wonder how many big bands covered Glenn Miller's "In the Mood" or "Little Brown Jug" adding their own personality to it, adding new instruments and making it their own.

I imagine that the prominence of clubs having live music/performers meant that at one time or another each famous artist of the time was requested to perform someone else's piece. Today, a band will usually play at least one cover song but they don't seem to go into recording as much as what seems to be the case pre-1950.