In that picture it appears the foundation rotated out of the ground. That would lead me first to look at foundation design and construction as opposed to turbine construction.
And here I was worried that in fifteen years, there would be mile after mile of these abandoned towers, standing like lonely and ghostly sentinels, scattered across the landscape.
So they will just fall down by themselves?
At least the salvage teams could then get at them. Lots of recyclable scrap value.
And soil-rainfall, as there’s a metric shite-tonne* of concrete in the foundation and lots of bolts as big around as your wrist.
* = typically 10-20 ft. thick, 60 ft. in diameter. 400 cu. yards weigh I g 2 million pounds.
Simply by inspection I have always suspected the foundations of these structures are insufficient since they are mostly just mass and not drilled in or piled structures from what I have seen. Just circular mass reinforced concrete of not a very big radius.
As a newly graduated Civil Engineer I saw the same kind of thing with heater treater units. Upon evaluation I found there is just no way they can stand in a gale with the simple foundations they had. They had to have guy wires but yet they mostly stood because when full of water and oil the CG is lowered. Some did have guy wires indicating prior problems.
There is a lot of sail area and moment arm on these windmill towers and yet they mostly stand up because of friction forces to the earth. Like an oak in waterlogged soil they will blow over when it gets too wet.