hi to beautiful BC - long may it last :)
My point was that when people wake up in the morning they care more about breakfast than checking the news to see if there was an earthquake. I'm not saying you don't care (at all) but ultimately that the level of caring is crowded out by, well, life.
Alas preparation (as much as you can) is a good thing, but the forces involved, and the sheer scale of the event (assuming a big one of course) will make preparations useful on a personal scale (my house didn't fall on my head, yay) but largely immaterial in the grander scheme of things.
Preparation will save lives. But the impact of the event will change everyone, prepared or not. Infrastructure will vanish, no roads, bridges, harbors, airports, rail. Food distribution, power, water, sanitation will all be off for extended periods of time.
In the long term one can expect large areas of unstable debris, oil and chemical pollution and so on.
Between the earthquake (perhaps a 9) and the tsunami, there's going to be a big mess, over a very large territory.
Regarding the west coast being untenable - mostly that revolves around infrastructure, and the ability to recreate it. Given the impact the event will have on the rest of the country (countries) the ability, or finances, to recreate it will be impaired.
Imagine you wake up tomorrow and Microsoft, Amazon, Apple, Facebook are just "gone". What would the ripple effect on other business be? Would that spark a recession? With respect to New Orleans, Katrina displaced 800 000 people, cost $125 billion, and roughly 10 years to reconstruct. And again, with respect, the cause of the disaster is trivial, and the result small, compared to a factor 9 quake, and 100 ft wave.
Imagine that playing out over the whole west coast, from Vancouver to San-Diego. The impact will be national, not local and it will be a long time before life on the west coast resumes in anything like the scale it is now.