yes a lot of cultures went extinct but not because they didn’t have writing. it’s because there was no one left to pass on the knowledge.

if we think about it from the perspective of contemporary indigenous people, they know how to read and write English but that’s a side effect of boarding schools. and it’s led to more intensive cultural extinction because of forced assimilation.

tldr: some tribes had writing before Columbus, some didn’t. cultural genocide is effective in both oral and written traditions