You know how you can tell that Speculative Fiction is artistically where it's at right now?
We're madly inventing subgenre after subgenre, most of which rely heavily on quality, literate prose. Like Interstitial. And New Weird. (And Urban Fantasy, Paranormal Romance, etc.)
Any other genre inventing subgenres at quite the breakneck pace?
Actually, I think that's not where spec fic is artistically; it's where it is marketingwise. "New Weird" was pretty much a pre-emptive strike; writers using the term to classify themselves before someone else does it. (Of course, that didn't work and now the people who coined the term as an attempt to control what they're perceived at nod politely when they're referred to as that.)
Second, I think calling "New Weird" or "Interstitial" genres is misleading. They're movements, or in the case of New Weird... Well, that one's like the skin left behind by the snake that's outgrown it.
Seeing that I often have trouble to tell the difference between Fantasy and Science Fiction, I never really bother with subgenres. The worst fate that can befall a writer is the unique mixture of ecclectic taste and an obsessive-compulsive categorisation drive.
Mumbling Sage said:
So are the speculative and literary genres coming together at last?
Not really, no. There have always been formally spec fic books marketed to the mainstream, and stylistically elaborate pieces marketed in genre. I've seen Bradbury's books in both category and mainstream editions, I think.
The main distinction is a social one: what books do you expect your readers to have read? A frustration with this compartmentalisation might explain Sterling's term "slipstream", actually.
It's fascinating to see how people try to be "fresh" and "new" by inventing a category to fit in. They do it again and again and again. It's nothing new. They invariably set themselves up for implosion, but most leave before that time. The poor unsuspecting tenants, though...