I feel your pain, NSW. Actually, I feel mine but it's similar to yours. I'm 3 years in also and have done more than is one your list and spent far too much. Far too much from what I envisaged and far too much to sell because I'll never get the money back. So that means... I'm committed to keeping her for the long term, maintaining and upgrading as I go, and enjoying as much as possible.
Yes, I'm afraid of the future expenses but I have almost all the big items (all except re-painting the hull). I've considered cutting my losses but then I look within and ask myself that question and the plain truth is that I just can't go back. If I sold her I'd... Well, I could I suppose. I could even be happy. But something would be missing. I have too many more miles to sail, skills to learn, whales to see, fish to eat, beaches to swim, weather to handle, places to discover, sunsets and rises, moonlit sails.... ah, the dreams, the dreams.
How long since you've had a good sail? We've had a crap autumn and winter until recently so I suspect you've not been out much. Plenty of whales around at the moment - there's even one in Middle Harbour!
And in 4 months it'll be December!