People don't (usually) pick a city to live in because of the cost of living, it is simply a good/bad side effect. Family/friends/job opportunities are what real

People don't (usually) pick a city to live in because of the cost of living, it is simply a good/bad side effect. Family/friends/job opportunities are what really affects the decision to go live somewhere. From that perspective it makes sense as an employer to try and give all your employees a chance of the same living standard, regardless of city choice. Also, from a employees perspective if you feel you're getting a lower wage than someone who is of less value to the company, you can always try and renegotiate your salary.