This trend is verified by the U-Haul index, the difference in the price paid for a rental truck leaving California versus what you pay to drive a U-Haul to California. It's a barometer of supply and demand as well as incentives and penalties necessary to keep a supply of trucks available at all locations.
San Francisco to Las Vegas $757
Las Vegas to San Francisco $313
San Francisco to Portland $1483
Portland to San Francisco $199
San Francisco to Seattle $1648
Seattle to San Francisco $353
San Francisco to Phoenix $1669
Phoenix to San Francisco $131
San Francisco to Albuquerque $2277
Albuquerque to San Francisco $716
San Francisco to Boise $2557
Boise to San Francisco $199
The Boise example is especially astounding!