it's a bit like saying the use of horse-drawn ploughs was a historical accident based on the failure to invent tractors

Ah, but a by-product of horse-drawn ploughs was that your fields got manured! You wouldn't then specify that tractors had to automatically manure fields as they went along, would you?

It's not a 'rule', it's a description

I'm quite happy to call it a description. However, for some people hereabouts - it's the law.

Mostly I prefer hearing and singing the first kind.

So do I, but that's my personal preference - so it doesn't count.