I’m going to take a wild stab and predict that JWM is a native San Diegan. I’ve noticed a sense of entitlement from native SD’s that they deserve to live in LaJolla or Del Mar or Coronado for what they consider an affordable price. Desirable markets don’t work that way and while I don’t know where to find the data, I’m very sure that the outmigration leaving SD county is probably 75% native SD’s who earn less than those people legally coming into the region. So while we see population growth supposedly nil (although there sure seem like there are way more people than when I moved here) I think there is more money moving here everyday. This will be especially true if SD home prices continue to go down.
As for the topic of downpayments, I was taught to save 20% of my take home pay beginning with my first job out of college. No exception. 1/3 went to the bank, 1/3 went to a short term bond fund and 1/3 went to a Schwab account. The easiest things to cut back on are living expenses and car. Live below your means. I easily had a 25% downpayment from the bank and bondf funds by the time I was 30 for what was then a $300k house in the Bay Area. Anyone with a decent job should be able to do that. I think the internet bubble and the easy money of the early 2000’s sent young investors/savers off the path. They saw their peers living in big houses, driving expensive cars and wanted to keep appearances up rather than taking the long term approach and continuing to save and invest.