The Yankees are still the same team as when Ruth and Gherig played there. The players come and go, but the team is eternal.
Glass never wears out, the physics of light do not change, and the site still is a good one. It's all that pesky support machinery that needs maintenance and replacement.

There are telescopes over a century old that are still doing valid scientific work. Some are irreplaceable, because the designs they incorporate were optimized for observational programs that have since gone out of fashion. No one makes them any more, if people want to do that kind of research, they have to make do with an instrument designed for some other application. And of course, when your country observatory is now surrounded by urban sprawl and mercury vapor steetlights, its usefulness can decline. All the fine Victorian machinery is sold for scrap, and the eternal, perfect objective lens or mirror, unimprovable even with the most modern technology, is crated up and buried in a warehouse somewhere. It is cheaper to erect an entirely new facility than to build a new observatory around the flawless heart of glass of the old one.

Observatories are holy places. They are as impressive and beautiful as a medieval cathedral and by necessity are usually located in lonely and desolate landscapes. Like cathedrals, they are temples to the ineffable, to the incredibly remote, and to our faith in being able to connect with it--places of worship, in a way, sacred places. I know it's sentimental and impractical of me, but if a site is to be abandoned, let it not be replaced with some practical symbol of the economy. Let it naturally decay into ruins, as a monument to our boldness, and to our stupidity. Centuries from now, men will stand in that place and say 'we once explored the stars from here'.