The issue I was aware of, was based on the concrete roof falling onto a car which crashed into the shelter in the early 90s.
That shelter was only a few years old at the time, so was repaired (and is still in use).

I think there is a programme to replace them all (just under 100 replacements a year), but dangerous, unsafe shelters will take priority. Guessing age and anti-social behaviour along with the location of an alternative shelter will play a part too.

edit: Here is the Gateshead Council policy https://www.gateshead.gov.uk/Transport%2...c/bus.aspx