Giant metal towers make a dead tall tree look harmless by comparison. If that topples - and eventually it will - it will kill everybody in its path. So, we're probably not going to just leave on-shore wind turbines to rot.
Off-shore definitely. The UK already had a bunch of decaying archaic man-made structures off shore because of World War II, the https://en.wikipedia.org/wiki/Maunsell_Forts which I went to look at a few weeks back. Pieces of the forts clearly break off and disappear into the sea without incident.
There is mostly nobody in the path of the tower, and once you remove the blades and the turbine (there is a lot of valuable metal there) the physical load will be so low the tower itself can stand there for a very, very long time. But of course it does not have to.
Off-shore definitely. The UK already had a bunch of decaying archaic man-made structures off shore because of World War II, the https://en.wikipedia.org/wiki/Maunsell_Forts which I went to look at a few weeks back. Pieces of the forts clearly break off and disappear into the sea without incident.