Microsoft is opening a temporary HoloLens showcase in New York City for new developers to introduce them to the company's coming holographic hardware and software.
Microsoft seems to be struggling to answer this question, as well.
That's a total of 120,000 devices worth an estimated $21.88 billion
The HoloLens 2 comes with better visuals (and a larger screen) and is easier to use. It is also more comfortable than its predecessor for extended sessions.