Creating a television show is as you've likely heard, a collaborative effort. It's also time consuming, expensive, and labor intensive. In cities like Los Angeles or New York or Vancouver B.C. the talent pool and infrastructure of gear, soundstages, and official cooperation can make the process more streamlined. But in Seattle while many of the pieces are there, especially the talent, it can be harder to make it a reality.
Series like Grey's Anatomy, ostensibly set in Seattle don't film here. Other films and television productions have of course been shot in Washington State going back to Tugboat Annie in the 1930's, or the last reincarnation of The Fugitive in 2000-2001, but in almost every case they were shows brought here by production companies from elsewhere.
Recently in West Seattle a local, independent production company, Corwood Productions LLC has been creating a segment for a prospective television pilot called The Divine Marigolds.