It does remove the flaw, because it's a thought experiment. It doesn't have to be plausible. It merely tests our evaluative judgements and intuitions.
But for most people, those drivers are not the result of abstracted thought to the point where they could not be satisfied by an artificial child. Most people, it seems to me, just experience the symptoms of the biological imperative, as opposed to any higher-order desire to propagate their genetic material. So I would expect it to be possible to overcome the preference for genuine biological offspring by, for example, designing the artificial replacements to look like the "parents"- especially if that resemblance was actually derived *from* the parent e.g. by scanning their features- thereby satisfying one of the symptoms of the imperative.
I think you need to read more of the writings here re: scepticism of one's own beliefs