Well, like I said, we'll have to wait and see.
There's really no reason to continue this. I agree with what you say above, and I think Proof is very capable of holding his own and doing what it takes to go platinum or double platinum. I think the verses I have heard from Proof prove he has great writing skills. Though none of his rhymes that I've heard of have reached this plateau, what I HAVE heard from him leads me to believe that when he tried, he CAN be ALMOST as good as Eminem.
Don't forget, Eminem met Proof when he was 17 and when they met, Proof was literally the top dogg on the underground circuit in Detroit. If you've ever seen 8 Mile, Proof had the clout in real life that Papa Doc from the Free World camp had. He was considered the best around, nobody could beat him, nobody could fuck with him. He had the respect of EVERYONE. Proof gave Eminem his "pass" to the ghetto. Until Eminem came along, Proof hadn't been been in a battle in like 2 or 3 years, and Em was the first to unseat him. So, I would say that Proof wouldn't have had that status if he weren't good.