Same as R&S released first one 12 bit, then another.
And I don't think I'm giving anything away if I strongly hint (tease?) that we're not finished releasing 12 bit scopes.
If I had four new scopes to release, I wouldn't release them all at the same time, even if they were all "ready" at the same time. NPIs (new product introductions) generate a lot of good publicity and "buzz" that extends well beyond the product being released.
An NPI is also a LOT of work - it's not just sending out a press release and updating a website. An important part of that process is working with industry influencers like Dave to give them early access to new instruments, and that of course does require some degree of confidentiality.
(and, ironically, I think this thread kind of proves that there is some merit to the "teaser" strategy after all ....)