In addition to the radios and other communications equipment on Slater, Gage was a source for many historical ship museums with which to backdate ships to WWII era design. In doing so, Gage herself had given up so much of her own equipment that by the time she was put on historical hold, she was stripped of so much equipment that it was hard to justify the expense of turning her into a museum ship.
The text describes how Slater's role in providing resources for historical ship museums and the subsequent depletion of her equipment made it difficult to justify turning her into a museum ship.