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Both word, and Google docs can do this, the results aren't always great but the function is there.

From the linked MS support document:

> This works best with PDFs that are mostly text

The problem isn't really if there are lots of images or graphics, but rather that word isn't great at handling complex layouts.

I somehow doubt OPs converter does much better. I hope to be proven wrong though.

The biggest problem is not Word's limitations in handling complex layouts, but PDF's complete lack of layout information.