So, lets talk cash.
That lens would be $2500-3000 and a streetprice of $2700 or so, based on Canon, nikon etc..
The coming house would probably be another $2000-3000 - atleast my guess, I don't think we will se a budget model that would cut too deep into the APS-C market nor a pro model that might cut into the 645z market, So something in between, maybe with a 36MP sensor. But in the end I can just guess since I do not have any specs.
Finally, a full frame with just a 70-200 would be useless, so we could expect a 24-70 or similar aswell at ~$2000 again based on Canon, Nikon etc.
There are just a few of the old FA* zoom lenses for sale at the moment.
As I see it there are a few possible outcomes,
1. the new lenses kick the old lenses back to the stoneage, and we will see more of the old being sold, this would then cause a price drop on the old lenses.
2. The new lenses are not optically supreme, and people with the old lenses keep them. The ones for sale will be more expensive in the future.
3. the new lenses are a little better, some people will change, some people will keep. Prices will remain about the same.
4. the new full frame camera will not have built in SR (look at the old mockup pictures of the lens, there are three switches, it might indicate that the shake reduction is in the lens instead) This will ofc cause a price drop on the old lenses since people normally want SR.
Edit: did not like the bird picture on this lens...