It’s actually closer to every 500 years at the latitude Seattle and Portland are at.
The 300 year figure only applies to the southern Oregon and Northern California portion of the fault, and is based on turbidities and controversial.
Still, this is an under-appreciated risk of living in the northwest. There’s plenty of societies living in subduction zones across the planet. But few with as little awareness of their fault.
I remember talking to transplants to Seattle, I’d say there’s a 50/50 percent chance they were aware the region could produce earthquakes.
On the bright side: while we can never predict this for certain, it doesn’t appear there’s enough energy stored in the northern portion of the fault to produce a mega-thrust earthquake right now.
Every tech worker I know who moved to Austin is here in spite the fact it’s in a conservative state, not because of it.
What it comes down to is the south has nice weather and is relatively underpopulated for historical reasons. Nothing else.
And frankly, having moved from Seattle, ‘powerhouse’ is an overstatement. Austin is a nice place, but has a long way to go in terms of engineering talent.