alt Hacker News> young folk these days
You should have stopped to think about why such a person was hired in the first place, while there are an endless supply of very talented, hard working, and honest young people who would never be given a chance at all.
But if I guess right, hiring is not seen as the responsibility of your company. And that's the core of the problem.
Sometimes people who are able to talk a lot do quite well in interviews - and University students need to be exposed to a wide variety of topics, but rarely support large projects for a long time, so that wouldn't be something that would come up in an interview.