I can see the point re internal market vs export orientation. But why make the housing market the focal point of wealth creation? Wouldn't the stock market be a much more overall beneficial place to let your population accumulate wealth (which the US also does quite successfully, through 401k, cheap and trustworthy financial products like ETFs, a strong SEC,...)?

Pushing house prices ever higher comes with so many societal problems, and also with serious financial risks. The start of Japan's lost decades, which you mentioned, wasn't weak domestic demand. It was a housing price bubble so extreme that small areas of central Tokio were worth more than all of California. Domestic demand was actually very strong in Japan up until that bubble burst. The biggest financial crisis in the US in recent memory (2008) was also due to the housing market, its consequences eclipsing that of the dotcom bubble or the 1987 crash. That being said, stock market bubbles are no fun either - the Great Depression of the 1930's was caused by a stock market crash. But at least stocks don't tend to push people into homelessness already while they're booming.