It's not super easy. A lot of these are apartments that are not easy to retrofit. And a lot of Seattle buildings, houses or apartments, have casement windows that swing out from the bottom to protect the interior from rain, but also are probably the worst type of window to install any type of portable or window AC unit into because they don't swing out very far but the opening is absolutely massive.
There's also the matter of the fact that because Seattle doesn't get very hot or cold, there aren't that many people or companies that do AC installation. Anecdotally I've now heard that they're booked out for months, possibly a year, and with tight local housing and job market that is unlikely to change. You certainly haven't really been able to buy fans or portable units anywhere in the area since May.
I know plenty of AMZN and MS employees without AC.