My general policy is "if you're not succeeding, change your definition/parameters of success until you are." Maybe you started with the definition of "success" being to make a beautiful, completed quilt with the pattern you chose, but something interfered. That doesn't mean you still can't learn from the mistakes you made with it or use the blocks for something else or use it for experimentation like new piecing techniques or quilting patterns or color schemes. Or maybe, as in your case, it will eventually get done but much later than anticipated- not only will you have succeed with your original goal, but you've doubly succeeded because you persevered for so long to finish it. Bravo!