The ‘market’ is definitely there, its just taking a little while to get moving.
I’m doing my university graduation project based on an arch-viz + oculus rift with a real residential model from an architectural firm. During my first meeting with them, I brought along my laptop and the realistic rendering demo and they were completely blown away. They wouldn’t stop talking about how far technology has come (they’re still used to just static screenshots of models or Vray renders) and the boss literally said he was ‘interested to see how we could streamline this and implement it into our workflow’.
Then I explained to them further that the photorealism was just the beginning. I then pulled out the Oculus DK1 and let them walk around in the realistic demo. Suffice it to say, they were beyond gob-smacked.
Trust me, visualisations with gaming engines is definitely going to catch on. Especially as more and more people get into it and discover it, and as technology just continues to get more powerful.
The only real setback is speed. As in, how fast you can crank out visualisations. The graphical fidelity and photorealism is nice, but if you can’t keep up with tight deadlines then it’s useless. As long as you can prove that the workflow is efficient and fast (which at the moment to be fair could be a lot better), then it’s very viable indeed.
EDIT: in terms of interactivity (like switching on lights, turning on taps etc), there isn’t a real ‘need’ for it. While it would definitely be nice as a sort of wow factor, a customer/client is not going to really care about being able to turn on a ceiling fan or opening a door in the long run. Especially since they’ll probably change their ideas on what they want which can modify the entire design brief anyway.