Dean, I've seen 1 (ONE) of these in the past ~20 years! If the supports behind the failing walls are in good shape, you can just re-sheath them with pressure treated 1/2 - 3/4" plywood. The biggest thing is that you won't know the condition of the original supports and plywood until you drain the pool, peel out the liner and take a look There are a lot of great new products out there that just weren't around when your pool was (probably) installed. If you are sure you want to redo the pool, the first thing to do is find out how bad the 'rot/ damage' is. I'm thinking that you can probably redo the pool for a lot less than 1/2 the price they quoted you (and they probably weren't even taking into account the deck and coping), but, as I said, I've only dealt with one wooden pool.
I hope someone else here has more experience with them and can give you more details. Good luck with the pool, if I can be of any help - please feel free to contact me