Why retire a space warship after forty years?

Would a space power really decommission a carrier after only forty years?

Yes; wear, technological obsolescence, changing ship scale, and crew efficiency can make retirement sensible.

Space does not remove fatigue, mechanical wear, or the stresses imposed by faster-than-light machinery. Technology can also move beyond what an old hull can economically accept. If drive economics favor steadily larger new construction, a forty-year-old carrier may be much smaller than current ships while still demanding a substantial crew. Retirement can therefore follow from the combined burden of wear, obsolescence, scale, and personnel efficiency.