That's a good point. The issue may simply be one primarily of framing in that text-based diffing and merging tools were not natural, so to speak, but had to be

That's a good point. The issue may simply be one primarily of framing in that text-based diffing and merging tools were not natural, so to speak, but had to be built. And even now, they're not great. I'm constantly irritated by text-based diffing tools because they barely understand anything beyond lines of text. I'm interested to see more semantic diff and merge tools built out. Regarding source-code control, I think it's a problem mainly of Git and not tools like Perforce or Plastic SCM which handle binary files that change over time better. It's also an issue for things like GitHub, which as far as I know, does not provide any hooks for custom diffs to be viewed in the browser.