i.e. 1. Employee moved back in with parents, not paying rent. Should company start paying them less because they need less?
2. Employee works remote from Arkansas, has 2 kids in college and is sending checks home to support mom. Company pays them less because... Arkansas?
How about the number we agreed on is the number we agreed on.
Cost of living in terms of rent or expenses is not everything. If I work from India, I also pay in terms of reduced life expectancy due to higher pollution, greater chance of dying in a road accident and what not. If a perverse sense of 'fairness' (or a facade of it) is so important to companies, I would love to see these factors being considered too.
The company agreed to pay you X amount because that's the market in the area you and the employer are competing in. Once you expand beyond that area the market changes. You're now competing against all of the other engineers from SF to Arkansas (and beyond). Let's put this way. If you're working from Arkansas, why should your employer pay you 400k/yr when they can just hire someone else in a cheap COL area within a reasonable timezone for a fraction of that?
As an anecdote from first hand experience, if your parents live close enough to your work (less than 2 hours commute) it's considered that you could live with them, regardless of what you actually do. Then, you cannot claim the $7k/year indemnity for accommodation. This is significant for a salary of $36k in this company (not in tech).
This is exactly what the company is doing.
They’re paying you the number you agreed upon until they don’t want to anymore (or until they’ve fulfilled whatever contractual agreements they’ve made). You’re not guaranteed to keep getting the number you agreed upon if your work sucks or the company goes out of business.
By the same token, you’re not obligated to hold up your end of the bargain any longer than you have to based on whatever agreement was made. Want to move to a cheap city and find a new high-paying job? Go nuts.