Many if not most of these convictions come from bad eye witness identifications. People whose knowledge of the law comes from TV think this is reliable evidence. In fact, it is among the most unreliable evidence.
There would also be fewer of these if juries took the guilty beyond a reasonable doubt standard seriously.
Eyewitness evidence is generally crap, and I would find it very hard to convict anyone based on nothing but what an eye witness said. Eyewitness is already reasonable doubt.
I think Juries are often stupid, and I think prosecutors are sometimes unethical.