My point is more "why do it?" than "can it be done?".
If a server is set up to only serve about 1/4th the US*, then why should there only be two US servers? Wouldn't it be natural to assume there should be 4? Or are you implying that there should be preferential treatment to those who happen to live in a state actually on the Pacific coastline? Because I can tell you my ping would be even less if there was a server in Denver, and players on the Atlantic coastline would have a smaller ping if there was a server in Atlanta.
What makes the West Coast so special that they can't play with the rest of NA? That they, and only they, should get their own server?
As I previously mentioned, Riot spent a lot more money on the POP system than they would have just making separate servers and splitting NA up. They did it to keep the community together, and as someone who has friends on both in the West and in the East I appreciate that. I don't think there's any logical reason at this point to ask for a West Coast Server. It would negatively impact my ability to play with my friends, and it would be a very noticeable increase in maintenance for Riot for minimal benefit for players.
* I'm limiting my comparison to the US geography since there's a lot of empty space in the northern parts of Canada and I don't know population distribution as well.