That just doesn't make any sense. You can't even rent an apartment for less than $3,000 in SF, let along think about buying the average $2M house. What is the discrepancy? Maybe these folks all ended up buying their houses 30 years ago?
The number doesn't jive for me either. You would have to go through how the median income number is formulated. It may not be how you think. I can't tell you the number of times I've seen this with broad statistics.