Only sort of.

If you need someone in the same time zone who speaks English at a level that enables them to contribute work of the same quality and volume as a native speaker, you've really only added Canada.

If you discount the language requirement, you can add Central and South America.

Only if you discount both the language requirement and the time zone requirement can you add the rest of the world.

I've worked in a global tech company, with development offices all over the world. It's very workable. Plenty of people all over who speak English well enough (once you get over the accents[1]).

Time zone issues are a bit of a pain, but manageable. As long as you don't have to meet with them daily, you (or they) simply schedule the once-every-week-or-two-weeks meeting at a time that can work (a little earlier in the morning or later in the evening). It was quite customary to leave early or start late on some days to make up for having a 1-2 hour meeting in the evening or early morning. This is well understood.

To be clear: Those developers were "first class" employees - treated similarly to the ones in the US.

[1] Indeed, although their accents may have been difficult to follow, the reality is they understand a wider variety of accents than do most Americans, and so Americans complaining about their accent would be viewed as petulant.

One of the hardest problems in programming is naming--variables, function names, abstractions, etc. A larger vocabulary (in English, the lingua franca of programming,) will enable someone to write better names.