Actually the FDOT did preserve the structure. They just did not do it according to your standards. They used the standard of federal law: The Secretary of the Interior's Standards for Rehabilitation.
Yes, a large portion of the materials are new but the character defining features of the historic bridge were kept and/or restored. What are the principle character defining features? Primarily, the towers. Secondarily, the steel arched girder spans. The towers are original, the steel arched girder spans are original.
So, you and I will not agree that it is "a copy." Further, you will not get agreement from FDOT, FHWA, U.S. Coast Guard, ACHP, ACOE, COSA, NPS, FSHPO, NTHP or any of the other involved agencies or organizations that recognize or are bound by federal law.