Quilts are quilted, which adds an extra layer of stabilization to seams. That means the 1/4" seam is enough.
When I have seen quilts fall apart after repeat launderings, it is usually because they were constructed with any or all of the following:
-too long a stitch length...use a shortish stitch for quilt seams (on that threshold of "short but I can still rip out stitches")
-poor quality fabric...low cost fabrics have a more open weave (less threads per inch) that does not hold the stitches well
-poor quality thread...there are some really awful threads out there
I had a lovely quilt given to me as a teen, made by a lady who loved to quilt but who was living on a very restricted income. She always used the lowest quality materials because she could not afford higher quality fabrics and threads. It was a real shame as her quilts would not survive laundering.
Making quilts is an expensive endeavour and getting more expensive all the time. But if you are putting all that time into the work, you really need to use the best fabric and thread you can budget for.