In my opinion, the logical assumption is that this spider species can't live for much more time than exactly that interval of time

The interesting point here to me is that it was not killed before. This suggests that it was able to fend off the wasps attacks for fourty years. I assume that hen died it was too weak (too old) to fight back. Another possibility is that it had moult recently and was too soft to defend itself.

Insects die soon because adult wings can't moult twice. Spiders don't have wings so they can moult indefinitely and became much much older than insects --but-- is easy to predict that (unlike jellyfishes), spiders can't live forever

We can be 100% sure of this empirically. We even could predict mathematically the life time span of each species, also if we would want it (again, in my opinion).