Assuming the $2000 figure is true, that's before you take your first photo. Film is MORE expensive than digital. Why do you think digital took off before the quality even compared to film?
I live in a country without a 5x4 film retailer and I'm not sure about development. So I'll look at UK prices:
1 pack of 10 sheets of 5x4 film: ~$40 (Robert White)
Development, per sheet: ~$4.50 (The Vault)
So the cost of shooting just 1000 images per year is $8,500 and that doesn't include the cost of many trips to the lab and back, and many hours spent scanning, etc. Clearly this gets expensive quickly. I shoot more like 10,000 images per year. Ouch.
Well some people have already compared a 39MP digital back to 5x4 film and there isn't a big difference. Scanning backs are already up to 139MP - ahead of 5x4 quality. I'm fairly confident that the next jump up from 39MP in one shot backs (60MP?) will match 5x4 quality, and it won't take 20 years to happen.
Using 4X5 solely for the resolution improvement is missing the point. The real advantage is having complete control of perspecitive and focal plane using movements. You can do things with view cameras built 60 years ago that are simply not possible with the latest DSLR, or the vast majority of MF cameras, including the newer ones designed specifically for digital.
And I bet there aren't very many view camera users who shot 1,000 frames of 4X5 in a year (maybe some architecture specialists, or fine art landscape guys). You just don't pull out your 4X5 and start shooting away blindly. Takes too long to consider all the possibilties, unless you're endowed with the talent and experience of St. Ansel or something. You may even spend a whole day looking for a great shot without ever setting up the camera. At least that's the way I work with them.
And there's the rub. If you only use a 4X5 to take a few dozen shots per year, it's going to be a long, long time before some sort of digital capture process can be justified in economic terms. I think rinderart is absolutely right.
Having said that, if someone comes up with a way to do full movements on a digital camera, for under about $7000, and without requiring some hyper exotic and expensive solution for wide angle lenses, I'll be all over it. But I'm not holding my breath either.