If citizens moved into a community because it was 'spacious and quiet' then it's 100% their right to keep it that way, and utterly bizarre that outsider should think they have the right to force some kind of change.
If community ABC does not want to be NY or Hong Kong that's entirely their perogative.
And FYI there's no evidence that 'density' decreases prices. The most 'dense' places in the US are the most expensive.
Americans do not have an inherent right to live in some place. There's plenty of land in the US meaning, Americans effectively have the right to choice, and to have some affordable abode, but that exists aplenty.
Now - when places like Atherton stop secondary projects, such as the electrification of Caltrain - now that's something else entirely - the community overall needs better transport, so Atherton needs to accommodate.
The 'solution' is probably to have much better/deeper/faster integration between transport services, how in holy cow is there not a 'very fast train' that goes around the bay, out to Sac, down to Morgan Hill, and up to Santa Rosa? With great connectors?
Frankly same with LA.
All of North and South Cal should be quickly navigable. That would make it more amenable to development.