Oh come now - globalizations was great at the regional level.

It was not that great for sub groups within developed nations.

The original thesis believed that people would be retrained into other equally well paying roles.

Turns out people can’t retrain into new domains, and led to under employment.

Why not, because they're too old to learn, or because the support infrastructure is not there? I believe most people are capable of continued learning, but they might need help (financial etc.) to make the transition.