A building might be 3 floors and have 12 units per floor, built 50-70 years ago. Each of these units rents for $800-900.
Now that Amazon is building 70,000 units of office space, people are predicting that another 70,000 people are going to be moving nearby for work. And so landlords are seeing a lot of people willing to pay a higher rate for these apartments. This requires evicting the ~24 people who live there, 2 of which (on average) will become homeless.
These landlords can either make the same amount of money, or they can make more money by raising the rent and forcing out the "average" people, confident that an Amazonian or other Techie will pay $1200 a month for the same apartment. And so the traditional residents of Seattle are being pushed out - to surrounding communities, to other areas, and out of the city they love.
A more drastic option is to evict all 24 people, demolish the building, and rebuild with twice the units at twice the rate.
Is this the fault of landlords for being capitalists?