It might help to taboo what we mean by "business need". Does it mean, "probably won't go out of business next year if I don't do this", in that case it is likely that I don't have a "business need" not to hire completely unqualified people as long as the rest can fill up the slack.

On the other hand, if "business need" means "this will make my business run better", then as Lumifer pointed out, it just happens that business runs better with smart people than with stupid people.