No, because a quote can contain a sub-sentence. The period adds meaning to the sentence by adding finality.

"You are going" has a very different meaning from "You are going.", because the first implies there is something `you` are going to do. Whilst the second implies you are being ordered to leave.

In that case, not capitalizing the word immediately following the quote will work as an indicator that the period is not part of the parent. This doesn't work in the case that the word following is a proper noun. But that's an edge case on something that doesn't really matter.

I agree that maintaining punctuation of the quote is important for context. But outside of the quote, it practically never matters if there is a period or not after the quote. The reader may choose.

> He looks up, "This is it." Bob says, gazing at the sky.

I agree with that, assuming there would be some indication if the quoted sentence wasn't complete.

I'm just saying that the outer/quoting sentence needs its own punctuation regardless of what's going on in between those quotation marks.

Then you have no signifier for whether the quote is partial or not. Did you quote part of something someone said or the full sentence?

So would you suggest that it would make sense to never have punctuation before a quotation mark?

Only when necessary.

E.g.: '«Are you joking?!», he said. The other replied, «I'm not joking at all». They went on'.