1 hour ago, danfling said:

soap opera historian Ron Lackmann speculates that "perhaps the story was too familiar, or perhaps once the basic story was told, there was nothing else to say about Kitty and her problems."

Looking at the schedule, it seems like it was the lone soap on NBC at that point, plus their inability to create a long running soap at that point bar Hawkins Fall (which "only" ran five years) and then a new format to boot? It was also against Art Linkletter at the time; still it was odd how quickly they gave up on it; Today Is Ours didn't do much better, so maybe they should've just moved it up a half hour to see how it did when From These Roots premiered to build a block.

6 hours ago, danfling said:

and then a 1942-44 radio serialization created by soap opera giant Irna Phillips

I have never seen any mention of Irna Phillips being involved with Kitty Foyle.

The serialized version on the radio was created by Irna Phillips and produced by Frank and Anne Hummart.  The soap opera was broadcast from October 5, 1942 to June 9, 1944 on CBS.   Its sponsor was General Mills.