I think it depends on the boat and on you.
I looked at one for my boat.
I typically keep my boats for 5 years.
Fisher quoted me $4643.00 plus tax and shipping, so let's make it $5000.
Now, also you have the cost of the frame, so that's another couple of hundred, plus remember, you need to put the frame up every fall, which I have seen people do it and it's time consuming!
Ok, back to the payback.
Shrinkwrap for my boat costs me from $10 to $13 a foot. So that is about $500 to wrap my boat.
That is everything, soup to nuts and I don't lift a finger!
Based on that, my packback is easily 10 years.
Throw in the hassle of the frame.
Throw in that you are laying out $5K today where shrinkwrap is only $500a season.
Throw in that the fisher cover needs to be cleaned, stored, kept dry, etc.
In my opinion, shrink wrap is the way to go!