So I think it doesn't quite miss the point. the point is that you want one ASCII space after a period and then you want the layout algorithm to do something intelligent (like make it as wide as two spaces or 1.5 spaces). This is why "1 space" is correct and two spaces conflates different layers of document creation (the textual information to display and how it is laid out).
I mean arguably then we would want a totally different character for end of sentence and not two spaces in a row. I think modern tools are smart enough to properly space "Mr. Foo" v."I was sad. John was happy." and if not you can always manually fix the spacing edge cases yourself without modifying the text.
> This is why "1 space" is correct and two spaces conflates different layers of document creation (the textual information to display and how it is laid out)
The problem is that I know of exactly zero programs other than TeX and the descendants thereof that are able to reliably distinguish between word-spaces and sentence-spaces without being explicitly told to do so (e.g. with double-spaces), and even then.
There are indeed different space characters in Unicode, and if Word wanted to do this right it would autocorrect <space><space> to, say, <en-space> or <em-space> (the way it already does for quotes, much to the chagrin of people including code snippets in Word documents).