Agreed.
Their slingshot is being undone exactly the same way that or was.
Just play one or two sweepers and slow them down and make them find targets in traffic.
The bit I dont get is why it took teams so long to work it out
My guess is teams trying to play their own way, trying to play the high press that is so common in the AFL, without adjusting to the opponent. (Also helps if you have the likes of Enright and Mackie sweeping, backed up by above average key defenders.) Credit to the Crows, they have absolutely smashed teams that have allowed them to play on those terms.