This is an odd analysis, because as it highlights, salaries are strongly correlated with wealth of the country. So the question really becomes, not why are salaries different, but "why is programming difficult to offshore". If programming was easy to import and export then either salaries would even out or, more likely, would be relocated to cheaper countries like many kinds of manufacturing. But software is difficul…
> why is programming difficult to offshore" Lack of professionalism and absence of a professional engineering culture in many of the places you'd seek to outsource to save money. Doesn't mean that professionalism doesn't exist, it's just that the ones that have it are already busy with their own thing and not interested in being low-cost labor
I used to work in a relatively "low salary programming culture" and it wasn't just the salary that sucked in that location, the programmers did too. Smart people either emigrated or ventured into a profession that made $$$ (typically real estate, management or finance). Eventually I left too.