I think US devs that work on high IQ projects have nothing to worry about. It's very hard to find high IQ devs outside of the developed countries - trust me, I've tried. Whilst there are some, they're not nearly enough to influence the jobs market (and they usually charge US rates). I think the local environment plays a big role - stuff like early childhood nutrition, healthcare, clean water and air, a good education system that can recognize and develop talent. That's usually missing in developing countries.

I do think there's a decent chance CRUD-related dev work wages will probably be suppressed. I think that's because the work is easier, so lower IQ people can do it well but also (and probably more importantly) a lot of that work is in the process of being automated anyway.