Seattle has a functioning local government that does things like approve building permits, an idea considered insane in the BA. I'll never understand how restricting building is meant to "preserve neighborhood character," when it actually results in pushing out long-term residents.
Honestly, I don't know why the transit politics are working so well here. Partly because Sound Transit has been unusually courageous for a political entity. They have successfully stared down the two richest areas in the region Bellevue and Mercer Island when faced with opposition.
Maybe it just comes down to propaganda. Quite a bit of money was spent to market ST3 to voters. Which is the most recent and most expensive transit oriented ballot initiative.
The whole time there has been a tremendous amount of work done to oppose the improvements. Many in the area will be familiar with the near constant efforts of Tim Eyman to defund transit projects
You might chock it up to uber lefties in Seattle but other liberal priorities have not faired nearly as well on ballot initiatives.