I think it's just that they are so young. Many people watching probably felt like they had been cooking longer than they had been alive. And these young guys looked too unkempt to be taken seriously. If they can't take the time for grooming and clean untorn clothing they probably aren't going to spend the time many dishes need to really be outstanding.
I think Duff is able to appeal to older folks because much of what he does is art, and not everyone feels they can do those kind of things. They were most likely trying to find another show that would have Duff's kind of appeal to attract different or younger viewers. It's not attracting your average foodie though and Food Network needs to remember their audience, this isn't it. It might attract a small group who would watch this one show, but they are not going to expand their audience doing that, and they are going to lose the viewers they already have. No longer than these guys have been at it, I think I have gathered enough info on my own to do just as well. They were not well spoken about what they were doing, seemed to goof off a bit and all that seems immature. Plus they have no wow factor like Duff. Duff seems very young, but that makes what he does all that more amazing, nothing these guys did was special ... original or impressive. Maybe they will gain what they are lacking in a few years and can try it again.
If anything good comes out of this show, my hope is that the Food Network realizes that we want people who can show us something new and they don't have to be 12 to know about new things. I want people who take what they are doing serious enough to show pride in how they present themselves and what they are making. Bobby Flay was fairly young when he started out on the food network and so was Tyler, but they looked and presented things like professionals.