A couple of factors that can affect real estate and distort the zones model.

1. The internet with VPN technology and tele-conferencing / video conferencing allows people to work remotely. So some people are moving away from the cities to cheaper (or more likely nicer) locations but still keeping good jobs and they are not overly affected by oil prices.

2. An aging population means more people are taking a sea change and moving to their rural or coastal holiday house for good, as a retirement. This will further support prices in the nicer areas rather than the places near the jobs.

In conclusion, the three circles in the diagram oversimplify what is a very complex demographic and economic puzzle. All ships will fall on the out-going tide but some will go down futher.

Tim