Some thoughts; again, total conjecture from me. If what you're describing happened more than a decade ago, the industry may have changed since then. I'm thinking of JLH's recent post about how the majors have tightened their operating procedures so that he can't now independently mix his licensed releases. In any event, what I described wouldn't preclude the major/pressing plant also pressing Mosaic's CDs on a just-in-time basis, with the quantity based on Mosaic's go-ahead.
Or: what you posted doesn't necessarily conflict with my post. As we know, Mosaic produces their own masters with their own mixes. If a pressing plant threw out Mosaic's masters, it might have cost Mosaic too much to recreate them, or they might not again have access to the original tapes to recreate them.
On a different subject, one more factor to consider: Cuscuna's nearing retirement age, as other Mosaic principals might be. It could be that all this is part of a natural winding-down of the label. It's not like they're a public company, where operating in perpetuity is possible.
To add insult to injury, they might have used the Mosaic box as a source for many of these recordings.