Writing 4 consecutive pixels at 0x0 stores those in video memory 64KB apart.
I don't think "64KB apart" would make much sense either, especially because of the flexibility of the VGA memory controller described in the article; they end up in 4 separate 64KB planes. Unless you're referring to the linear view of the framebuffer that post-VGA GPUs use, in which case the mapping between the planes and LFB can differ considerably between implementations: https://stackoverflow.com/questions/36269239/meaning-of-byte...
Yes. Bytes land in separate planes which afaik are 64KB apart in video memory if you would/could access it linearly. I think it was performance driven decision in the design of EGA with 4 parallel ram banks enabling 4x faster solid color fills etc. Both MCGA and VESA VBE cut all that crap out only allowing linear buffer which greatly simplified hardware interface unlocked new optimization possibilities.
All VGA clones still have to at least pretend mode 13h writes are divided into planes.
Personally I never think of them being 64kb apart since you can’t access it linearly (without vesa at least and all the stuff I do for VGA is pre-vesa). I think of it as stacked planes.