Fair point, the sentence I invented off the top of my head isn't perfectly grammatically correct but it's close-enough that it shows the ambiguity problem. It's a lot to ask text-to-speech and typesetting programs to figure out contextually which periods are abbreviations and which periods are end-of-sentence, and so having a hard text cue like double-space would help. Then typesetters would have a hard cue of when to replace the space with a thin-space (which is supposed to happen in the case of something like "H. G. Wells").