Dandy -- good point. However, I've seen all the other art movie houses in DC close (without competition) over the last 10 years, and they haven't been replaced, so, hence, I'm looking forward to Landmark. I'm not sure how to insulate Visions, but to me, the rest have all caved or gone under already. I think Dupont will always be alright because it's in such a good location for people to pop in.
I saw this with independent bookstores in the 90s -- my dad's profession. Outside of the largest cities, they're gone. It's all Borders, B&N, etc. It's a good point, and I've been conscious of it in the past. But, alas, I have to admit I'm probably feeding into it these days (though I still shop at Olsson's whenever I can).