There is NO market where “ASIL” is required.
Of course if something happens you better have a safety case as described in the ISO26262, or a good excuse.
That being said, that a system has a safety case according to ISO26262 ASIL D, does bot mean at all that all pieces must be certified.
Currently working in a project where ASIL D is reached by having an independent microcontroller, whatching out the whole QM mess.
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.
It's not legally mandated, but the dynamics of the regulation and the risk-averse nature of companies mean that it's effectively become a requirement to compete: if you don't have it, you're only going to sell to the rare company that is willing to stick their neck out and deal with novel arguments in the paperwork themselves. For commercial aerospace that is none of the manufacturers.
(someone else might come along and certify it themselves, effectively acting as a middleman, but then they're going to get most of the money)
Currently working in a project where ASIL D is reached by having an independent microcontroller, whatching out the whole QM mess.