I too have quilts that I've finished the top, or almost finished, and then don 't get around to quilting it! I too have way too many irons in the fire. I crochet, knit, sew, applique, cross stitch, needlepoint, I even used to do stained glass. One year I was really mad at myself for not finishing things and made a New Years promise to myself to finish unfinished things. For the most part I finished! Now I guess I am back again! I think it is partly the creative process. I am interested in new techniques. I dive in and learn and then get bored! I also get sidelined by agreeing to make things, including quilts for church. I always put them before anything else.
Try not to beat yourself up. If you want to learn how to finish a quilt there are a great many tutorials out there. HGTV used to have Simply Quilts on it. I feel sure there was how to do that in the archives. Also quilting bees, societies, are filled with wonderful quilters that will help you.