I'm not sure what "family" housing means. Does this imply that families can't live in apartments? There is also a difference between affordable apartments/duplexes within a few miles of downtown and a $175k 2500ft2 house on 6th and Lamar.
For every example of cities with good "street life" and "vibe" with low rise architecture, there are many that feature tall buildings as well. Many, many Asian cities achieve this (Hong Kong, Seoul, Tokyo, Singapore, Shanghai, etc.) as well as in Rio de Janeiro, Santiago de Chile, etc. In every city mentioned there are many more midrise buildings that intermingle with the high-rises. And, for the most part, they do a good job limiting the depth of setbacks from the sidewalk which goes a long way toward enabling first/second-story retail and food.
And of course I could fill an entire thread with lowrise cities that aren't very walkable/bikable, like most of LA, Jacksonville, etc. Heck even the aforementioned Portland and Miami have much lower levels of public transit usage
than the two "tower cities" of NYC and Chicago.
The main keys to vibrant streetlife are dealing with the lower few stories of the buildings and making sure that the setback from the sidewalk is not very deep - this is a big problem for Dallas IMO. Also helpful are areas alloted to food stands, sidewalk cafes, and even sidewalk retail (clothing racks, newsstands, bookshelves). The mix of uses is important too - the Boston Harbor area feels deserted on weekends, because like many American downtowns it has zero residential, which also means a LOT less retail and "interesting" food locations. The key common denominator is that MOST vibrant streetscapes need a very high level of "organic" pedestrian traffic to be successful and sustainable. There can be one or two per city though that attract enough car traffic to replicate this vibrancy.
South Beach is an area that most locals drive to, park in the garage
, spend the day, and leave. To me this is a "destination" area that is a point of congregation for tourists and people from all over the Miami Sprawl - similarly, the Wailea mall and beach in Maui is quite "vibrant" though it's hardly a triumph of urbanism or a replicable model.
Austin can have multiple destination areas as well: Lady Bird Lake, eventually the Domain. These areas can and should have a lot of 4-7 story apartments and offices nearby, which is finally happening today on South Lamar and Riverside near the Lake. But we can still build a ton of towers downtown, especially since this will actually supply people and $ to "feed" the kinds of streetscapes that you're so fond of, austlar. As cities like New York, Boston, Toronto and San Francisco - to name a few in our continent alone - show, it's not an either/or proposition.
BevoLJ, I totally agree that keeping/attracting jobs to the urban core is key to creating a good ecosystem long term. The Cirrus Building is a decent example, though it and other area office buildings - I work in one nearby - go way overboard on the amount of built-in parking IMO. If the perceived need for built-in parking goes down, the square footage yield per $ of building cost will (hopefully) increase over time.