You are right, on reflection, there has to be a sponsor, I expect no one from West Seattle applied.
I guess it is a considerable expense to build one, insure it and pay the permit every year. At least California south of Alaska is relatively flat so construction could be minimal (not like the one already built in front of Montana Bar on Capital Hill).
I still think it would be a great addition to that locale.
It’s possible a parklet could be sponsored and crowd funded by a non-profit such as Sustainable West Seattle or WSBC, with the agreement of local businesses, but not sure how they could handle insurance issues.
Maybe as the high rises go up and begin to fill up people will begin to see the need for more open space in that crowded pedestrian corridor along California Ave SW.