It’s muscle memory. Imagine how inefficient you’d be if someone moved the vowels to a different spot on your keyboard.

While both keyboards are nearly the same, everything you type would be wrong for quite a while.

Is it though? Ignoring the fun stuff, I just email, read (datasheets and text)books (i.e. PDFs and phone people on my phone - how much muscle memory is there in the first place?

Unless you mean the wider ecosystem, in which case I agree.