1) 16mm dupe's that have been sitting around for 25 years would barely yield detail any greater than the sources we have now
2) the condition of the film would be so scratched, marked and damaged that it would effectively render them near uselessness.
The amount of work needed to clean up and restore the print to something that would actually benefit us would be pretty irrational to take up. Add to that the cost of a proper scan--not just a cheap telecine done with a camera, but an actual film scan that would properly translate the detail so needed to be wrung from this sort of source--and you have thousands of dollars of expenses on top of thousanads of man-hours of work. And at the end of the day it would be far less than say, what an X0 version of the film could yield (hypothetical that such a thing exists--but my point is that if you bought an X0 player, used the best LD, and obtained the mastering software this would be a far better--and still-cheaper--way of going about it).
This is purely a quality thing I am talking about, mind you. In terms of personal home viewing--a film print, even a scratchy 16mm one, of a Star Wars film is such a joy to watch. If you have the equipment to play it I would recommend getting them just for your own personal enjoyment, but chances are you don't have a 16mm projector and proper sound recievers.