as an american, i never liked the inside rule, although it does "look right" to me from being taught it all through school.
the comma is not part of the quote, so it shouldn't be inside, typographical systems be damned. i tend to put it outside, to the horror of (american) grammar snobs everywhere. i think programming is what got me to seriously reconsider the placement.
I read long ago that the American convention comes from an old printing press limitation and flowed into writing too. This answer [1] on English StackExchange has some details. I’m sure many other sites have written about this in detail.
Seems implausible to me. As one of the replies indicates, most periods at the end of lines won’t follow a quote, so this solution doesn’t work there.
Worse, it only applies to lines ending in a period. Those are extremely rare because hand-set lines typically ended with filler, in order to make all lines in a block of text equal length. See for example https://letterpresscommons.com/setting-type-by-hand/: “ As you are setting your line of type and finish the last word of the line, you’ll need to fill out the rest of your line with word spacing material”
I also would think most exclamation marks would not be wider than periods and commas. Why, then, are those typically rendered outside closing quotation marks?
“According to William F. Phillips (wfp@world.std.com), in the days when printing used raised bits of metal, "." and "," were the most delicate, and were in danger of damage (the face of the piece of type might break off from the body, or be bent or dented from above) if they had a '"' on one side and a blank space on the other. Hence the convention arose of always using '."' and ',"' rather than '".' and '",', regardless of logic.”
I don’t see obvious objections to that explanation.
Thanks that makes it clear yes I was taught outside (from Australia) and I didn't know there was an inside rule, I must look out for that in the novel I'm reading
"Hacker News is," he said, "a website." (American)
vs.
"Hacker News is", he said, "a website". (British)
We Americans are taught to always put punctuation inside the quotation marks, with a few limited exceptions.
I gather our cousins across the sea are taught not to do this.
It's started to bleed into my own writing given the international nature of the teams I work with.