All the rentals I looked at had fixed prices and they weren't interested in extra cash. That's also assuming you're renting from an individual and not a company. The massive apartments that are being built have fixed, though rising yearly, costs.
> property taxes have risen 35%
That increase isn't automatic and certainly isn't locked in step to the number of people moving in. Its a decision by the county.
My point is that to blame people trying to find a place to stay is ridiculous. The increase in pricing is a choice made by landlords, and is influenced by a choice made by the county.
The county's choices are a reflection of its citizens. City council has recently passed several new ordinances to make housing more 'fair', unfortunately this also has caused a significant increase in compliance cost for property managers.
My personal opinion is that zoning should be relaxed in several areas. Nevertheless Seattle price/sqft is in the range of other major US cities and still has room to rise:
https://www.rentcafe.com/blog/apartment-search-2/what-does-1...
Also, in order to cope with rising costs from new residents, property taxes have risen 35% in the last 4 years [0]. Part of the rent increases are just to cover the property tax. These taxes are voted in by the people.
(Source: I have friends who have purchased homes here, others who work in real estate, and I do tech things for property management companies.)
[0]: https://www.seattletimes.com/business/real-estate/property-t...