femtoparsec

Don't forget that often (but certainly not always) CEOs will look ahead and try to get a feel for which locations may be a good fit both for their personal and company affairs. Usually due to taxation, regulatory, hiring, cultural, cost of living and a range of other realities. They may make the move themselves ahead of their company's move making it seem like the company later moved merely because of the CEO's new location, but they'd already made the decision that the company move would follow as the sensible thing.

As the employer, it often works differently. You interview a number of people as final candidates you find good fits for different reasons. Each person presents some extra benefits and some shortcomings. You then balance it off against the costs of hiring each person, and you make a final decision on that basis. At that stage, someone who'd be an appropriate "right next step" for the company at $80K may not be the right next step if they were at $100K, so you may pass if the person isn't willing to accept $80K.

If you truly run into cases where the hiring decision has already been made, so you're sure you're hiring the person independent of where they live, and then decide you'll pay them less if they live elsewhere - then one of 2 things is happening. Reality #1 - you're being subjected to some kind of corporate level accommodation where the business has decided that "we'll just take the hit and up-adjust salaries based on cost of living". If they don't apply this approach universally, the only alternative would be to either pay everyone $100k and therefore not have the ability to hire as many people, or simply not hire from $100K markets and only hire from $80k. Reality #2 - there's some real corporate corruption happening at the company where they're doing this for the sake of some central policy, but it's not a real constraint. That'd be unfortunate.