Median net worth stasis: health and demographics?

Salmon of the Trinity [1] notes that Median net worth has actually been static for about 30 years. So we can either fund social security, or learn to live with elderly beggars, or invest in Soylent Green.

It's a fascinating result; seemingly consistent with other studies on long term wage stagnation. I'm looking forward to more discussion, including ...

1. What is the effect of demographics, in particular what is the mean age of the median net worth over the past 30 years? We know our population is aging, and we know net worth increases far faster in one's 20s than in one's forties.
2. What is the relationship to savings? (Presumably, other than "housing", it means we're not saving - see "social security")
3. How much of this is because of health care and education costs? How much more expensive is it to raise a child in 2010 than it 1980?
4. Is there an "occult inflation" contributor?
5. Is it coincidental that this stasis corresponds with the widespread dissemination of programmable technologies?

[1] Krugman, Klein and Salmon