Totally agree, I've seen 1 aircraft salvaged from water that actually made sense, a republic Sea Bee, simply because it sank over night, and wasn't bent going into the water, the wing skins are very expensive and worth the time to take them apart and clean. ( they are rare as chicken lips)
and other aluminum skinned aircraft simply isn't worth the troubles, because in today's market you can buy better aircraft than you can build.
To actually recover a salt water soaked aircraft made from aluminum you would be required to completely disassemble the entire aircraft, bead blast the aluminum and reprime and reassemble the whole thing, this would require a fuselage fixture ($10,000) and a wing fixture ($15,000) all new wiring, all new instruments, all new radios, new engine, prop, new interior, and about 2 years labor for 3 people.
do the math. $$$$$$
The easiest aircraft to do would be a rag and tube type, then you'd have to be very selective about how many complex systems you must deal with.
IMHO if they are in the salt, they should go to the crusher.
I'll retract the 1 aircraft recovered from salt that made sense, the Boeing that ran out of gas short of BFI, and went into the salt was recovered, but now sets in the Smithsonian. There are probably others.