“if you can get the same house in Temecula as 4S for less than half the price, you will see people make that trade-off, which will pull buyers out of the desirable areas.”
This is already the case today in some cases. For all of the people I have taken over to 4S all of none of them would even consider places like Temecula. It is highly impractical and people are not going to trade a commute from 4S to Sorrento Vally for a ride out to Temecula.
I am not saying nice areas will not depreciate. They may even match the depreciation percentage wise of less desireable areas. However the timing will not be the same, as this is clearly evident. I also still believe, and of course this is only my opinion that in some nice areas the depreciation will not match the less desireable areas percentage wise.