> Most people in ESTA countries qualify

Correction: most citizens of ESTA countries qualify. For example, approximately three million Canadian residents are not citizens of Canada (they have work permit, study permit, or permanent residence permit instead). Wait times for a visa appointment from Canada are about 1 to 1.5 years now.

Fun fact: permanent residents of the US can visit Canada without needing a visa, but this is not reciprocated. Permanent residents of Canada need a visa to visit the US, unless their country of citizenship is one of the ESTA countries.