From the 1960s continuing through the 1970s Australia (1966), Canada (1962) and the United States (1965) abandoned race base immigration laws. Within ten years, Australia and Canada developed an employment-oriented immigration system. This 2020 Bipartisan Action Committee report by Cris Ramón and Angelina Downs explains how this happened there and not in the U.S. Key to an employment-based system, the report says, is centralized policy making in the executive branch and heavy involvement of economic elites. This political culture allows for drastic changes on policy based on evolving facts, and with the acceptance of the public. This is not present in the U.S.
In the United States, the die was cast in the 1965 immigration reform act, which conservatives in Congress tilted towards family based immigration expecting that this would allow European-heavy immigration to persists. Also, there was no investment in the Executive Branch towards creating a power to devise and manage an employment-oriented points system – as was the case in the other two countries.
In the United Kingdom, the open-ended immigration policy for Commonwealth members was shut down by acts during 1962 – 1971. The “hostile environment policy” of recent years sought to extirpate Caribbean immigrants from the years before 1971.