Even if I am wrong -- even if the majority of alien civilizations turn out to be biological -- it may be that the most intelligent alien civilizations will be ones in which the inhabitants are SAI.
SAI is her term for "superintelligent artificial intelligence". So she has just written a tautology. Unless you want to get into super-superintelligent or ultra-superintelligent.
And the rest is more of the same.
Or maybe intelligence is weakly ordered, and "most intelligent alien civilization" has as much meaning as "biggest civilization". I.e.: most intelligent/biggest according to what measure?