Define “required”. If every single legal department at every single major automotive company says “we must obtain ASIL-B certification for our gauge cluster software or we can’t sell cars”, does it matter if regulators don’t overtly mandate it? The legal environments of all of the major automotive markets make it a de facto requirement.
The ISO26262 was defined by the automakers themselves (almost all were represented in the committee) so yes, they want to follow it. There is no legal requirement. It does not specially help in case of litigation either.
Define “required”. If every single legal department at every single major automotive company says “we must obtain ASIL-B certification for our gauge cluster software or we can’t sell cars”, does it matter if regulators don’t overtly mandate it? The legal environments of all of the major automotive markets make it a de facto requirement.