at last, we agree!
it will be reasonable to essume there are redundent copies of a gene.
in fact, we know there are, the phenomenon of redundancy of genes, and of metabolic pathays is well documented.
also, the existance of pseudo-genes (mentioned in this talk many times) is a indirect proof for such redundencies ,
as they used to be genes, but the body tolerated their loss of function (because they had doubles).
another point to take in mind is the regulation of expression, mainly feedback-inhibition, which means the more protein is created, the less it will further be created.
in this kind of regulation, the original amount of proteins will stay the same even if the body will make duplicates of the gene.

if I may diagnose you for a second,
your problem is not with the lack of knoladge, but in your rigid concepts, which you continiusly stick to : good-mutatuions, bad-mutations, ussless-proteins, and so on.
these are all simplifications, the data we knowy shows us that they are all ralative and not constants..