The Tyson's area is shopping central for so many people that I would think the Vienna store will remain. It has better access than the larger malls, IMO. That area is shopping on steroids.
The whole DC metro area seems to be booming with tons of new construction, condos, offices, shops. And H can't increase its business if it doesn't max customer exposure. I think these various venues would serve different clienteles, as someone pointed out. And, I can't imagine the NM giving up its H boutique as I believe it's the only NM that has one. It's not a huge boutique but always interesting to visit, and so forth. Plus, the clientele can use their NM and accumulate points or whatever.