You want to make a virtual copy of the uncropped original, and crop that. You are starting with the cropped virtual copy, which won't work.
Unfortunately, the uncropped originals have not been retouched, which means that I would have to retouch all 250 images again, if I wanted newly (wider) cropped images that are also retouched.
I believe I proceeded initially by first cropping the original images; next, exporting (saving) these cropped images to a new folder, - then did the retouching on these cropped images from the new folder.
Any way around this predicament? Again, want to recrop the images while retaining all the hours of retouching invested.
Non-destructive nature of LR a myth?
Thank you for your concern.
Non-destructive nature of Lightroom is not a myth, unless you make the process "destructive" by exporting a photo and then importing them for retouching. I would never recommend exporting and then importing to do further edits.
You can still copy the editing you did from the retouched images to the original, but I think you'd have to do this pair-by-pair (there may be a plug-in that does this globally, I'll let someone else speak about that). Then once the edits are copied, you can create the virtual copy and then crop.
In the future, you edit the original, then make a virtual copy and crop. Go back to the original and make another virtual copy and crop again. And so on.
Thank you for your feedback on how the process works and your advice on how to handle future tasks involving retouching, cropping, and recropping. Very helpful advice for next time.