The talk of the restoration of the Warner Chan's have come up often on this site and the general answer is: Not much can be done with the bad copies of the films that are left.
Yet i'm a bit miffed at the fact that restoration of one or any of the Warner Chan movies has not been explored more.
Some of the Gray market Chan prints/copies are bad but do not look beyond restoration.

Old movies that appear to be farfrom being restored from copies that are bad or poor, cna actually be done. i recall when TMC showed a Chan marathon, that they were a race against time to ave classic movies. Some have perished. The film turned to dust.

This is a good topic for discussion. The problem with the majority of the grey market films is that they are 16mm which offers much less detail than a 35mm print. On a commercial DVD the difference would be readily apparent.

Although there have been many advances in technology, restoration is still a time consuming and very expensive process which has its limits. While tears, cue marks and dirt can be fixed, the underlying image can only be improved so much. You can't add detail that's not there to begin with. At about $100,000 to restore a single B&W film, the costs to restore an entire series can be enormous. For example, Fox reportedly spent over $2 million restoring the Chans. They would have sell a lot of units to recoup those costs much less make a profit.

Restoration of the print also assumes that it isn't brittle or warped. Monogram was a budget studio and didn't have high production values. Even when brand new, their prints probably were a notch or two below the majors in terms of quality. Add in 50+ years of poor preservation at the hands of the various owners and you can get a sense of the challenges that Warners faces.