It's not as easy as you might think. All the boats belong to someone and declaring "salvage" comes with some risks and responsibility. There are deals to be made, but it takes quite a bit of leg work, as well as jumping through several legal hoops.
The insurance companies get first dibs, then come the folks that have incurred costs, such as marinas with unpaid service, slip fees, recovery and rescue operations. Next up are the private salvage claims, which can get tedious with the paper work. Lastly if derelicts are to be broken up, someone still owns them and they get the proceeds from the break up, after costs (paying someone to break her up for it's equipment). In many cases, the equipment isn't worth the labor to remove, so the whole lot is set to the land fill. In fact, it usually costs them to drag it there. It's a cost versus reward thing and the margins are slim at best.
Lets look at a common 25' sailor. It was sunk or shoved up onto shore during the storm. It's rig is toast, the engine full of water and worthless, ditto the transmission, electronics and much of the electrical system. You can recover ground tackle (what's a used 25 pound anchor worth?), maybe the sails, if below and bagged and can be cleaned, these could be sold. Taking controls out of them usually isn't worth the trouble, as most are application specific. None of the soft stuff, like cushions, curtains and other items will be worth salvaging, so you're left with a hull shell, liner and deck cap, much of which may also need repair.
Simply put, out of 100 potential prospects, you might find one or two that have hope, at least in regard to equipment, if not restoration. This is a pretty discouraging premise, if you're doing the leg work, walking through yard after yard, looking for a deal. This is one reason insurance companies and owners walk away fairly easily. They look at the costs associated with repairs and it's a simple business decision. If you're lucky, you can recover a very meager portion of the yacht's value with hardware sales.
I've had some luck with this, but I've also taken a number of "baths". It takes a good bit of experience to know which yacht is worth taking these types of risks on. In some cases you can walk into a marina and get an opportunity to strip a Catalina 25 (for example), for a small fee. It relieves them of the bother and they get to make something. You can also make an offer on the whole boat, which is waht they want, so you don't make a mess or get hurt in their yard, "doing the deed". In the end, the only effective way, is to do the leg work and make friends with these folks. They want to free up the "dead spots" in their yard for paying customers, so you're doing them a favor, but they have to be cautious too.