Imagine having not just two spaces but a whole damn line to emphasize the pauses in text:
https://en.m.wikipedia.org/wiki/United_States_Declaration_of...
If two spaces causes you to stab your eyes for this I demand no less than seppuku
https://en.m.wikipedia.org/wiki/United_States_Declaration_of...
If two spaces causes you to stab your eyes for this I demand no less than seppuku
Within sentences, there's the dash—either em or space-en-space, depending on where you're from—and there are plenty of other structural options. Between sentences, you've got the ellipsis, and that's it. The way they're used in the Declaration, in place of paragraph breaks, is helpful even when you're not just trying to save space—for example, to structure a list of short words or phrases without creating the visual separation from the text that comes with using separate lines.