Why elderberries are dying?

Wild elderberries (Sambucus nigra) are native to my area in Poland. They are wonderful plants, providing me with flowers and fruits. Recently they have started to die out. There are no obvious symptoms of disease, older bushes simply start to have more and more dead branches and finally do not "awake" after winter. What might be possible reason for that? It is far from any pollution, other trees are doing fine. I read that elderberries live up to 60 years, these have less than 30 for sure.

Apparently, elders are susceptible to verticillium wilt - there's quite a bit of info out there -here's one link I found here maybe it's that?