Singapore seems too socially conservative, though.
Some more fuel for Austin:
While the comparison is not made directly in this article, I think there is somewhat of a tick vs. mosquito trade-off being made specifically between the NY/Peekskill and Austin sites, given that NY is just barely out of the mosquito area on that map, and Austin is right in it.
But I mention this to say, as a native Southern Louisianan, I'd be far more wary of getting Lyme disease than being bothered by mosquitoes. Mosquitoes, while sometimes annoyingly resilient to repellents and things, are simultaneously rather fickle ~ a slight...
Austin is not "Western, desert, dryer air". It's usually 60-70% relative humidity. (https://www.weather-us.com/en/texas-usa/austin-climate) While those are basically the same relative humidity numbers as Berkeley (https://www.weather-us.com/en/california-usa/berkeley-climate), in the summer it reaches that level of humidity while temperatures are in the 90s or 100s.
Dry western air starts a little bit west of the Balcones Escarpment, which Austin is at the foothills of.
Austin is noticeably less humid than Houston. But it's nothing like the dryness of California. It actually has the same annual precipitation as Seattle (just in a few big storms, rather than a constant drizzle).
I completely agree with your points about cars, but I don't think Portland is in the running here. I am wondering what other areas may be most walkable, livable without a car. The US is such a car-centric place, that it's tough. Europe would obviously be much better for that.