i am sure my hand piecing is just as strong as my machine quilting since it depends on the strength of the thread being used. i use good quality strong threads and i make tiny stitches. i have had machine stitching come out with time...i have never had my hand stitching come out.
many people piece quilts (and make other things) by hand...they hold up for decades...hundreds of years...the strength depends on the materials used...not necessarily the techniques used