Yes, quiz shows test recall as much as knowledge. Some people just seem not to be able to recall what they know, at least not easily and quickly, or not when under pressure. At other times your mind can get in a muddle, and something you should know you just can't get a handle on for whatever reason. Examples including muddling two people up with similar names, or just pressure making you doubt yourself...
On the other hand, quiz shows that give away cash prizes have a tendency to pick people less likely to win those prizes. Either way, until you have been on a quiz show or at least tried to get on one it's unfair to presume stupidity. It's more likely to be trouble coping with pressure, to some extent.