Apparently not everyone has picked up on the population shift. Partially due to the cost of housing east of Seattle, there has been more growth on the west side of Puget Sound. True, West Tiger signals cover Seattle and the East side well, but my signal strength monitoring shows a South Mountain advantage on the west side of the Sound, and the growth on the west side has been quite remarkable. I wouldn't be surprised if at some point some of the traditional "Seattle" signals would add a "rim shot" and simulcast, thus covering the whole market.
By the way, one can still buy a 1,600 sq ft 3 bedroom, 2 bath new home on the West Side for $500k.