At the risk of angering the people who so strongly opposed the mixed-use project for the Curtis Chevrolet site, I'll go on record as saying that I strongly disagree with their stance. Housing Complex boils down the reason quite succinctly.
Here's the bottom line: You can't demand fun, high-quality, neighborhood-serving retail without accepting more residents. Brightwood isn't high-density or high-income enough to support the kinds of things Speaks and Co. are asking for, and when you oppose mixed-use projects, you're just asking for a Walmart.
GGW follows up: Want a Trader Joe's? Then add more residents.
It's simple. Unless your neighborhood is in the process of growing rapidly, it's unlikely to get more retailers and probably not the kind you want. Most of the time, the retail market is close to an equilibrium where the number of retailers matches the demand for retail in that area. Only when a neighborhood is gaining population is the time ripe to add more.
Once upon a time, the commercial corridors thrived without this added housing, except for two factors. First, family sizes were substantially larger, and a typical single-family house might have parents, 3-4 kids and even some relatives living there. Now, family sizes are smaller, but many neighbors also fight proposals to allow basement or garage apartments, even though those would simply restore the numbers of people that the house used to hold.
Second, people shop more online and more in suburban big box centers. That's not going to change. Bringing big box retail into DC, as these Wal-Marts do, might keep more of the tax dollars from big box shopping in DC, but won't create healthy neighborhood shopping corridors.
Neighborhoods can either stay the same size, and see local retail gradually decline as online shopping grows and DC adds big box stores. Or, they can add enough new residents to support new retail options. Most of us prefer the latter. Some people, though, want to stop new residents but also have the retail. That's completely unrealistic.