So the current approach is something like:
The elimination of transition areas in parts of Austin that are most vulnerable to gentrification and displacement.
This begs the question as to how this will affect development and hence affordability in these areas long term. Given the supply/demand imbalance in Austin as a whole and specific areas to an even greater extent it is important to ask how will these lots will develop when the densities allowed are so low. I would imagine in the short term very little will change and older smaller homes in gentrifying areas will stay inexpensive relative to newer homes in the same area. In the medium and especially long term, and if the zoning is expected to stay stable - like as in the previous cycle of 1984 to 2020 - then I would expect property owners to maximize the utility/ROI of these parcels. This would mean a single family 800 sq. ft. house built in 1929 will be torn down and replaced with a maxed to impervious cover house of around 2,000 sq. ft. that is very expensive. Given the by-right ADU a slightly less expensive home could be added to the back. In the end I don’t thing anything will be preserved as the advocates of this want and at that price that they want because in the longer term everything will be built to highest and best use. In other words intentionally down zoning is not the tool they want given the stated goals of council.
One side note is that making tear downs harder does not really help with affordability since there is still the ability to remodel the existing layout and expand from there. The idea that this is cheaper than scraping and starting over is not anything I’ve seen a lot of evidence for. I’ve seen remodels in Holly neighborhood that have taken over a year and one was almost three years, or about the same amount of time for KB to build an entire subdivision.
The main side effect of downzoning is that like a balloon the air inside does not disappear when squeezed it just goes to another part of the ballon. The counterargument to this is that upzoning incites development where it would not normally be otherwise, but since there really aren’t many areas of Austin considered undesirable by developers and would be renters and owners this really doesn’t hold water. I think this idea only works if a certain area is considered off limits for whatever reason, but when you see area like 12th and Chicon being developed that’s all the proof you need that that bird has flown the coop.