As s3dave says, you should always get more breaking if you price the bits right and have the time and patience to do it.
Practiically though, most people don't have the space to leave a car on stands as it gradually gets broken down, and nor do they want a gradually broken down car sitting on the driveway.
The other thing is how do you value your time? Don't underestimate the endless phone calls/emails that you will have to deal with as well as the actual time to remove the bits. Do you have the time and knowledge to remove the engine for instance, or even the time to supervise somebody doing it so they dont damage the rest of the car or take anything else? At some point, all the big bits will be gone, and you'll still have to arrange a breaker to come and get the rest.
In this case, it's probably better to just sell the car with a known gearbox fault.
Depends what you're going to do next with regard to a car, and budget etc.