No problem. Most of those would be ratio group giveaways. There are some groups which require users to maintain a ratio on giveaways sent:won. So people just don't enter giveaways they don't think are worth it.
There might also be restriction giveaways, for example Playing Appreciated requires players to play the won game within a month. So if it's a game people aren't willing to play then it might get 0 entries.
The rare case would be if everyone in the group already has the game... in that case even if the game is good it'll get 0 entries.