I also used to live in Japan. Construction has to follow guidelines to ensure they comply to earthquake standards and Japan is one of the leaders in earthquake - proof technology. Part of this may come in the compromise of 'thinner walls'.
This in part also explains why tearing down a house and building a new one is desired, as you would want the most modern earthquake proof property.
I haven't lived in a place in Japan that wasn't double glazed and central heating is not really required since most of the year heating is not required (at least in Tokyo).
Without trying to sound 'patronizing', you sound a bit like a foreigner who hasn't yet fully adapted to Japan.
Without getting into the general argument here, I'm just going to dispel a few misconceptions about earthquake engineering:
No one (basically) who is involved in earthquake engineering would ever use the term 'earthquake-proof' to describe one building, much less an entire country's construction practices. Instead, we generally design buildings to not require any repair after earthquakes which occur more frequently than once per century, and design buildings not to fall down after earthquakes which occur more frequently than once per 2500 years. There is always a chance that an earthquake will occur outside of those limits, and nothing is designed to withstand those.
While you are correct in assuming that adding weight to a structure (all things being equal) will increase the seismic forces it experiences, the contribution of sound insulation to the weight of the building is pretty insignificant. And for lightweight structures it is much easier to increase their strength than to decrease their weight.
Third, earthquake resistant 'technology' [re: design practices] is not as ever-changing as you might think. While there are some examples of innovative solutions like putting water tanks at the top of skyscrapers, for low-rise structures there really isn't that much to it. If you take a 100 year old house, screw some plywood sheets between the floors, and bolt it to the foundation, then it will be 90% (estimated) as safe as a brand new house. Earthquake resistance is not so much about technology, and is more about making very sure that all of the force generated in the house can make it to the ground without breaking anything (though physicists would say that the force goes in the other direction from the ground to the structure). This means that earthquake safety is fairly proportional to the amount of time and money spent on construction, which is very much not incentivized by disposable construction.
There are many other earthquake-prone regions which don't rely on thin-wall, disposable architecture.
What you generally will see is an aversion to unreinforced masonry construction -- stone or brick. Where you do see these they've generally been substantially reinforced with either internal or external metal skeletons (or you live in a region with poor building codes and the structures were erected since the last big temblor).
I'd suspect that Japanese construction methods follows engineering to some extent, but is also strongly influenced by tradition.
chile also has earthquakes and seems to be completely different (the buildings i have lived in have had thick walls - they help keep the building cool in summer - and there is a strong second-hand market). so i don't think earthquakes explain this.
This in part also explains why tearing down a house and building a new one is desired, as you would want the most modern earthquake proof property.
I haven't lived in a place in Japan that wasn't double glazed and central heating is not really required since most of the year heating is not required (at least in Tokyo).
Without trying to sound 'patronizing', you sound a bit like a foreigner who hasn't yet fully adapted to Japan.