I am sorry, but you are confidently incorrect.
It is absolutely true that x86_64 and ARM are two different CPU architectures, this does not mean that RAM usage differs hugely between them, that has more to do with the OS.
If you want to load a 20MB raw image into ram to edit it, it will take 20MB of ram regardless of CPU arcitecture.
The reason we are used to using so much ram is that as hardware capabillities have increased, so have software requirenments.