I think there's something that might be perceived as a quality decline, a decrease in how alive the text feels, as Wikipedia follows its strict notability policy and, as a result, gets more and more academic and dry as the more creative/informal/adventurous writers cannot write the kind of texts they want, and therefore move to smaller, more informal, wikis, where on-topic-ness is the criterion of inclusion rather than notability, and it's applied rather loosly.
I think there's something that might be perceived as a quality decline, a decrease in how alive the text feels, as Wikipedia follows its strict notability policy and, as a result, gets more and more academic and dry as the more creative/informal/adventurous writers cannot write the kind of texts they want, and therefore move to smaller, more informal, wikis, where on-topic-ness is the criterion of inclusion rather than notability, and it's applied rather loosly.