The location based pay argument depends on if you're an average or superstar employee.
Average employees (e.g. building CRUD websites) will get location based pay because that's what the market dictates.
Superstar employees, people that are unique on the global scale, will get superstar pay, regardless of location. In the Spark world, there are few people that are able to understand the source code, optimize Catalyst plans, write huge data processing pipelines, etc. These types of employees won't see location pay adjustments.
Basecamp pays superstar rates for superstar employees.
Factory workers that perform "routine functions" earn location based wages.