Friedman wasn't merely arguing that this would give rise to better companies - the crux of his argument was that by adopting this "fiduciary duty" standard, it would be easy to determine whether a company was being well-managed or run into the ground:
pluralistic.net/2024/09/18/f...
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pluralistic.net
Pluralistic: There’s no such thing as “shareholder supremacy” (18 Sep 2024) – Pluralistic: Daily links from Cory Doctorow