If you click through to the eventual source, the cost is the predicted amount that will not be added to GDP. I am not sure that really qualifies at a cost.
Yes.
> To who?
It's creation of value that would otherwise happen that is not happening; its a net cost to the nation as a whole. Which particular firms and individuals are paying it is, perhaps, harder to determine.
I still have a tough time with reduced government spending being considered a cost.