The construction quality of multi-family homes in SV pretty poor.
I moved out after my first lease expired.
Nowadays codes and trends - at least in parts of Europe - caught up, and soundproofing has became important through the process. (For architects/engineers, developers/builders and buyers/renters.)
My point is that properties above entry level apartment grade are scarce in the valley despite the fact that rents can support it better than just about anywhere. It actually kept me from moving up there
And you can hear your neighbors cough.
We can do better, and yes, I'm willing to sacrifice the superficial stuff and pay a bit more for quality construction.
I also run a box fan almost all the time, so quieter sounds from neighbors are below the noise floor and not perceptible.