Does it say if PSP in the summer is a 737 or Q400? I fly it a lot even in the summer via SFO or SEA (SEA is not daily in the summer, just F-M) and there are only 20-30 folks on the SFO flight who continue from PDX on it in the summer.
Also I doubt an evening SNA flight would return, they gave up the slot for that flight and more importantly it's early morning PDX return.