Much as with computers, in modern infocentric warfare, 26 is an eternity.
That said, these mothballed ships were cruisers of the modern type with minimal hull armor. Their hulls are worn out and need replacement. Replacement costs a significant part of the price of a new ship and results in an old, slow, limited combatant that’s more a liability than an asset.
You may be thinking of our Frigate fleet - the Oliver Hazard Perry-class, decommissioned after only 20-24 years partly due to the hull issues (among other reasons).
I was referring to the Ticonderoga-class missile cruisers, the six oldest are being retired about 6-8 years shy of their 35-year life-span.