> Also, if you read some other threads on HN, there is a strong sentiment that Bezos is "shaking down" North American cities to determine which one is most willing to bend to his will for a secondary headquarters

There's also some sentiment in the Seattle investor/business community that Amazon is using the opportunity as a threat to the city. That it's willing to expand somewhere else if the city doesn't become more friendly towards Amazon's demands/preferences. This certainly lines up well with the idea that Amazon announced a HQ2 without actually naming a city, leaving the media buzz and PR to influence the city of Seattle.

Though these are all rumblings I've heard and should be taken with a grain of salt.