Hi Tim,
First off, rather than dwelling on what a person can't do, or do as fast as a person could in the past, consider the journey you have already been on.....how many people even start to build an airplane? You have already gone further on the journey than most earthlings who never even tried. Nobody and nothing can ever take that away from you. Likewise, your Ercoupe is a wonderful aircraft and not only have you built up your kitfox to it's current state of near completion; but you have a great airplane to fly...without rudder pedals.
A lot of truth in what Esser has communicated...that's solid thinking.
An experimental that is not complete traditionally will only go for a fraction of it's value as a completed aircraft. Even if you don't fly it, if you take the time you need to complete it you will likely recover much more of your investment. In the process, keep the remaining construction basic and do it in a manner where the finished product will have as wide appeal as possible to the cast of potential buyers.
You know, I think we all run into challenges in life...and unrelenting pain is bearcat ...the only variable is which challenges and when we run into those challenges. Back to the solid thinking....none of us do this to become zillionaires....we do it for love of activity.....maybe a good way to assess challenges like this is consider what would make a person happy, consider what would not....then go with the positive one - so often I think it is easier to decide if a person objectifies the extremes.
Good luck with your situation and decision process; and, always remember the journey you have been on no matter what you decide.