I used to be in IT in St. Louis. IT is definitely an industry where people move all over the country following the work on 1 to 3 year stays then moving on. So it was/is common for small businesses like ours to recruit from all over the country.
St. Louis is a big, but definitely 3rd tier, US metro area. Our cost of living was about 10-15% less than the nearest 2nd tier city Chicago. Chicago is very similar to St Louis in culture, geography, politics, and climate. Cross flow of workers between the metro areas seems pretty natural and low-friction. But …
When we tried to recruit IT talent for working locally, not remotely, anyone coming from Chicago wanted the same dollar wages they had been earning. Essentially they didn’t believe the cost of living was lower and/or they believed that a resume’ or work history showing a nominal wage reduction would be detrimental to their future career and hire-ability.
Meantime folks coming from lesser cities or lower cost-of-living areas all wanted raises to offset the increased COL.
In the end, my firm wasn’t persuasive or attractive enough to persuade Chicago talent to take the cut, nor were we big enough to have the resources to pay the extra they demanded. So we ended up with almost nobody coming from larger cities.
Big picture any company needs to pay whatever it takes to get talent to show when and where needed to do the tasks needed. Back when doing work for an NYC company required living in NYC with all the attendant high costs there, they had to pay more to get folks to show up. Once the NYC company can get the same work done by folks living in Fargo willing to work for Fargo money they have no need to offer those folks NYC money.
The hard part is the transition, when folks hired at NYC money living in NYC move elsewhere but keep doing the same work. The other transition is when what used to be [gotta be in NYC work] suddenly is [can be done anywhere* work]. The employees were being paid a locality differential in NYC, even if nobody on either side of the bargain labeled it as such or recognized it as such.
The actual value of the work to the employer forms an upper bound on what they should decide to pay for it. But it is generally a very loose upper bound and they are often able to get the work done for far, far less than its value to them. This seems especially true in the middle layers of income from WAG 60K to 300K.
I say “should” above because we’re all familiar with the upper-middle and upper-upper management folks who’re adept at delivering negative value to the company while extracting vast sums for doing so. Meanwhile at the bottom of the wage scale it is very possible for marginal work to be priced out by high wages. Where the value to the employer is below the lowest wage they can pay and still get takers.
* Can you say "Bangla Desh"? I knew you could.