The difference is, most tech companies aren’t selling the product/service exclusively in the region that the worker is working in, so the cost of the product/service, say for example Amazon prime, is the same nationwide despite the differences in cost of living, but the employees are paid regionally.

Basically: most tech companies don’t adjust the price of their product for the region they are selling it in, but adjust the salary of the people making the product based on the region they live in.