When we were in Washington in 2014 they were doing a major removal project and the average cost to them then was $50,000 per vessel. The difference was likely they were not in as bad a condition as the one you mention plus they were at docks. They were pulled ashore by front end loaders and then crushed a few feet at a time with the scraps loaded into dumpsters and hauled away.
Fortunately, the Florida boats of this thread are being removed while they may still have some salvage value and, at worst, can be destroyed by regular salvage people.
In Key West a few years ago there was a major problem of abandoned derelict boats left at marinas. This was before the current law which allows state or local intervention. The issue was that the marina ultimately became the owner of the abandoned vessel and then they could be liable for any damages such as environmental. They were scared to move the boats and get them to land. So, the solution. A lot of boats hit E-bay and Craigslist and were sold for anything from $1 to $10,000 with the provision they had to be removed from the marina. People paid $10 and then found out the cost to move it would be $20,000, which they didn't have. I know one boat sold to a homeless man for $1 and the marina helped him get it running and got him on his way. He did get away from the marina, although not very far, before it started sinking and the Coast Guard had to rescue him. The estimate I heard them for removal was $500,000. I don't know what ultimately happened.
Marinas, and we the public, are victims of their own complacency for decades. They didn't have and enforce standards. As long as they got paid, they did nothing. Even when the boat owner stopped paying the slip fee, they were slow to act and the laws didn't provide them much help.
Robbie's has a sailboat in Key West that legend has it is in the same spot it was blocked over 20 years ago. Storage is paid every month but when the owner dies I bet the kids don't claim their inheritance.
And in my opinion Florida contributes to our problem with allowing "classic" boat designation. Older boats are cheaper to register yet many times more likely to become derelict. When I look across Stock Island at the junk boats there are few if any paying current state registration fees. And in the interest of the public good if you have upgraded your 30 plus year old boat with new propulsion you can't get the reduced price registration. Smart. Old boat with old engines=cheap registration. Old boat with new engines=pay up. And then we don't require liability and recovery insurance. Not saying other states do better but no one in the Monroe County tax office is fooled with where some of these boats they register are going to end up. Seems to me we might ought to look at the problem using the "generally speaking" concept. Generally speaking the older and less valuable a boat becomes the more likely it is to end up derelict. Maybe boats 30 years and older should have to pay more for registration and be required to carry salvage insurance. It would certainly help the situation. Although insurance companies as a general rule are smarter than most state legislatures and those policies on a 50-60 year old boat would be $$$ or not available. Just some musing from someone who looks at the problem every day when we are in KW.
Don