OK, having had a strong business background from a previous part of my life:
There are many excellent reasons why VSL cannot reply to these kinds of questions, nor - IMO at least - should they. VSL has chosen the business model of silence, and that is that.
For one, if they were to announce, "We are currently working on the mostest brilliantest fabuwonderous strings library the sample world has ever seen...
All I will say is remember not too long ago when one certain company announced in advance a particular library, a certain "compass directional" company immediately announced far in advance their own competing library of the same type? What was the likely end goal: to impact sales of that first company's library by encouraging people to wait to see if the "compass directional" company's forthcoming product would be better. That second announcement by the "compass directional" company did impact the publicity of the first company as it got many people talking about the second company's forthcoming plans, to the detriment of the first company.
If the competition does not know what VSL is working on (which they would if VSL publicized it), those other companies, won't be able to try to circumvent things, etc.
Howver much one may wish for an announcement, it likely will not be forthcomng. IMO, one of the secondary ways VSL has been able to stay "on top" as it were, is that the competition has very little idea of what VSL is actually doing.