Turning a novelty that is unappealing to most people into a mass market product is damn well revolutionary. Not many companies are able to pull that off. (Sometimes that transition is more gradual and evolutionary - I would argue that was the case with digital cameras - but sometimes it's actually a single product that makes this transformation happen. I would say the iPad is the prime example for that. Sometimes it's something between evolution and revolution.)
Yes, inventions do matter - but turning mere technology into products people actually want also matters. Both can be evolutionary, both can be revolutionary. Sometimes (though probably rarely) it's possible to do both in one step, often it's not.
If the Rift catches on with more than a handful gamers and starts a sustained era of affordable, high quality, low latency head tracking 3D HMDs it will be a revolutionary product - and it doesn't matter even a little bit if something a bit like it existed 30 years ago.