That’s a nice thought, but big telescopes are not known for being designed to last that long (other than the 200 inch on Palomar).
The cables suspending the flying structure at Arecibo were failing, and the engineers responsible for the maintenance of the telescope were surprised by this fact. They had no plans in place to replace the cables periodically. This implies that the telescope lived as long as the designers could have hoped for, given their inability to precisely calculate the fatigue life of the structure in its operating conditions and maintenance regimen. (I’m not saying they were incompetent, I’m just saying that it’s very difficult to predict structural lifetimes.)
Big telescopes often have structural problems; they’re just not made known to the world. both of the big, rotating, cubical telescope enclosures on Mt. Graham in Arizona had to have their wheel bearings upgraded after a few years, as the original weight specifications given to the wheel designers didn’t get revised after the enclosure designs were completed (with extra weight added during the design process). This is the sort of mistake that is endemic to the world of things designed for scientists.
In short, this telescope design did pretty darn well.
