It ain't just Austin. All the major cities in Texas are consistent blue zones. Take a look at the map below. San Antonio, Austin, Houston, and Dallas are easily found by their color... and it ain't red. Plus the border counties which are politically controlled by Hispanics.
Don't be fooled by the amount of red on the map. Geographically, the majority of the state is red, but most of these areas are sparsely-populated rural areas. The representative power of the large cities is larger than it appears on the map.
While I feel it would still be a LONG struggle for liberals to gain a majority in this state, it does bear watching. Their disease is growing, and unless the trend changes, it's only a matter of time before they gain control.