not only does hamed lose to barrera at any point in their careers he loses to any elite fighter. Hamed was not going downhill, he was still a young man. It was simply his lack of skill and arrogance catching up with him.
I think there was some decline when they fought. but not too much. don't forget hamed put in arguably his best performance a year before against Bungu. that was pretty impressive. his defence looked ok in that fight The first real test that Hamed had was in 1997 against a still good Kevin kelly and he was made to look awful. luckily enough he landed the bomb. but things could of went the otehr way N
Fighters prime at different times. Tyson peaked early and Lewis peaked late. Regardless, Hamed was going down hill cause he wasn't training properly and focusing on the fights - one of the main reasons that he split from his trainer Brendan Ingle.