I wouldn't even say it's the core principle of software engineering. It's not really a "principle" anyway: legacy is just a reality that we have to deal with.
And a perfectly valid way of dealing with it might be to throw it away and rewrite it. That's not a choice to be taken lightly, to be sure, but it's complete nonsense for the article author to suggest it isn't an option.
And a perfectly valid way of dealing with it might be to throw it away and rewrite it. That's not a choice to be taken lightly, to be sure, but it's complete nonsense for the article author to suggest it isn't an option.