Most of the unconscious nonverbal cues we experience can be captured just fine visually.
I agree that haptics and smell are much longer-term technologies. But making you smell a certain smell is "just" a question of poking the right neuron. It doesn't require any magic, just a lot of engineering.
Coming from a neurology background, 'poking the right neuron' is a ridiculously difficult task. Then there's the vast gulf between "can you smell anything at all when we poke this" and "can you smell sea spray when we poke this".
I would also disagree about 'most' unconscious nonverbal cues. People behave differently talking to a camera, and pick up a lot more in person.
How do you experience smells in a digital system, without reverting to sci-fi magic?
Edit: to be clearer, a lot of human communication involves non-verbal cues, often made unconsciously.