You can start with a shallow product and slowly build it up with user feedback to create a defensible and deep product. The key is to continuously improve it.
I'd be very interested on any ideas about how to make deep innovation less risky. For shallow ones is "launch fast", but what to do when this one is not available?
Well, a lot of them have. Besides "you often can't" is not very helpful.
The question is whether it's more difficult because you started as shallow or not -- not whether it's not a 100% surefire way to make it.