Conversation so far:
Where did the voice ideas come from?
Marge's raspy voice is only slightly different from Kavner's, who has a "honeyed gravel voice" which she says is due to "a bump on [her] vocal cords..
Has she always been voiced by the same person?
During a pay dispute in 1998, Fox threatened to replace the six main voice actors with new actors, going as far as preparing to cast new voices.

Question: What happened with that?
Self-contained rewrite: What happened with Fox threatening to replace the voice actors?