Does it matter to remove portability to platforms we don't care about any more? It's a question with no objectively/universally right or wrong answer. The obvious counterpoint I'd mention is big endian: is it worth fixing your endianness bugs? Or is it ok to assume little endian since the vast (VAST) majority of software does not care about the very few remaining big endian platforms? 32-bit could become a similar situation. It happened with 16-bit, right? Nobody today cares whether their modern code is portable to 16-bit machines.

More generally, I disagree with absolutist takes on programming. There's no right or wrong in programming. There's just requirements and choices.