As it stands, the rigs are brought ashore, dismantled and cleaned to a standard you could eat your dinner off. The billions this will cost are effectively lost tax revenue. The rigs could be cleaned up in situ to a lesser but reasonable standard. Yes, this might result in a greater chance of environmental damage. But the billions lost to public services carry a certainty that many will receive a lower standard of education and healthcare.
There is also the possibility of great environmental gain. The rigs sunk in deep water could form of a huge artificial reef in a marine environmental protection area.
David J Hogg