There are already facilities like this (obviously not as new as Rubin) degrading due to funding, but this is because there's usually no better purpose for them.

There are already facilities like this (obviously not as new as Rubin) degrading due to funding, but this is because there's usually no better purpose for them. Space monitoring has been used in the past as a second life for facilities (outreach too), but ~1m class telescopes are good enough now that networks of them are better than a 40+ year old telescope. It's also worth noting bits can be reused: buildings gutted and repurposed, telescopes/instruments moved/sold on, etc.; but the real issue is having the staff to look after these places, and many older facilities are not always as amenable to automation as people might like (especially funding agencies). Arecibo was about 60 years old for comparison when it collapsed, but there are lots of faculties that are effectively ships of Theseus, with new instruments coming in over time which refresh the faculty (and when that stops happening, then you get concerned).