I thought I was specifically taught that this is why you do two spaces. It isn't that you need two spaces after a sentence, per se; but the system has an easier time knowing to do inter sentence spacing instead of title if you do that.

That is, Dr. Smith should have less spacing. I'm guessing there are so few things that that applies to, that most systems that care can just hardcode it nowadays?

Further, I thought any typesetting system would play with the spaces after words to make things pleasant. That is, a space isn't a set width in any typeset thing. That really only became a thing with typewriters.