Not really. They bring the same benefits regardless of community density. So talking streetcars coming to DC or Jax is no different from talking about them coming and bringing sustainable development to Tampa, Dallas, Little Rock, Kenosa, Tucson, New Orleans, Memphis or Portland.
I politely disagree. I think that in SunBelt cities, you need to create walkable places first, from revitalized downtowns to mixed-use developments to lifestyle centers and the rest. You then link those places together via the transit system. A great deal of this has to do with the capital cost of building the streetcars/transit lines in and of themselves: density matters. Regarding the politics of transportation, demonstrating that a lot of people are using the transit built is essential (or the highways win!) The key here is density.
I often reflect on South Florida with regards to transit, as I was born, raised and educated there. In Miami, the MetroFail was built outside of downtown, away from density, removed from downtown Coral Gables, Coconut Grove...and never even went to Miami Beach (still doesn't. Idiots.) This meant that, unless you were going downtown, you had no reason to use the MetroFail. You wouldn't use the train to go to a nightclub in Coconut Grove...because it's too far to walk there.
It was only 20 years later that the Metrofail stations got the density they need to be effective, with the development of "Downtown Kendall," and a few lifestyle centers/mixed-use places along the line (and indeed: the system is still not effective because it hasn't been maintained. It's a fourth-class transit option, behind the car, the bike, hitching a ride with a serial killer, and walking.)
Contrast this with Broward and Palm Beach Counties, vastly more pragmatic and steady in their governance. Both of these counties are quite auto-dependent, and realize that, for the time being, they aren't going to get people out of their cars anytime soon...
...but they've taken a measured, long-term approach to the future via what I call the "fake downtown" syndrome. Mizner Park in Boca, The Walk in Coral Springs, RiverWalk in Fort Lauderdale, Las Olas in Fort Lauderdale, Abacoa in Jupiter, CityPlace in West Palm Beach and the rest (and there are now slews of them, ranging from malls in town drag to full-on mixed-use development,) not only remind the car-buying public what a great and wonderful pastime an urban walk is, they are a step in the plan. Create "something" from "nothing." Take those "somethings" and string them together with transit. This way of development contrasts with Tampa's as well, whose success with the heritage streetcar is mixed, at best (although, to be fair, they really have given it their all, and it's a well-defined, intelligent plan.)
Does this mean that South Florida is still basically car-dependent? Absolutely. But they've already put down brushstrokes on their canvas to go from that place to the next. Removing the toxic stew that is transportation politics in the South, I'd place both density and transit on the same level: you should encourage and develop both simultaneously. Placing back in that stew most foul, I'd seriously follow the Broward/Palm Beach approach. Broward is expanding their bus system, creating a downtown streetcar (I think,) and actually is mulling over the idea of light rail. That's an astonishing accomplishment from a region known for its huge highways, its 8-lane "local" roads. Part of the reason for this conversation about transit is the success of their attempts to densify. They can now make the valid point that we have the cart. Now, we need the horse.
