I think one useful metric is what percent of the population falls inside of the overton window that makes you unemployable in any upper middle class job (ie jobs that make it possible for you to acquire power). Jared Taylor, for example, was a translator for law firms for a long time after publicly and prominently saying that immigration should be curtailed for the sake of keeping the white percentage of the population higher. It was a quite unpopular view even then but it didn’t matter because whatever, it’s just his personal political views.

Nowadays, even believing something that half or more of the population believes is far outside of the Overton window and will ruin your career.