I've seen this in my hometown in Ukraine. It has ~20 outsource companies in different sectors and if you're good at doing what you're doing and kind of swapping jobs, there's still a ceiling they wouldn't want to break for you despite usually being paid by US citizens for their services. It's easy for companies to get new trainees and juniors as city has 2 universities with CS courses and everyone seems to want to work in IT.

Most of folks who want bigger salary either move to a city with product companies (Kyiv, Odessa, Lviv, Kharkiv, etc), so there's natural competition and outsource rise their salaries too, or go remote.