I feel that the relevance of "Friendliness theory" depends heavily on the idea of a "discrete jump" that seems unlikely and whose likelihood does not seem to have been publicly argued for.

It has been. An AI foom could be fast enough and/or sufficiently invisible in the early stages that it's practically discrete, to us. So the AI-foom does have relevance, contra

I believe I have read the vast majority of the Sequences, including the AI-foom debate, and that this content - while interesting and enjoyable - does not have much relevance for the arguments I've made.