To confirm the claim that "all scales in all cultures are based on octaves and fifths" one might study the scales.zip scale files and find those that do not contain octaves and fifths, which should naturally be zero if the claim is true.

https://www.huygens-fokker.org/scala/

Note also that certain musical traditions were suppressed or eradicated due to their unfortunate habit of using dissonant notes such as minor seconds, as opposed to the consonant traids favored by a particular group recently in power around the world. Happy Easter!