TBH I think it depends on the coat. I've had a golden and a white with Black and Tan, both of whom kept their silky backs with only their legs getting fluffy. I managed to keep their coats silky with a coat king and thinning scissors.
My blue roan I had to clip right from the start, her coat was like cotton wool. My solid black, I hand stripped upto and for about 18 months after her spay but then had to resort to coat king and thinners. Gradually it too longer and longer to groom her, the last one being 4 hours. In the end I thought who am I doing this for, and it certainly wasn't Ebony. She is now clipped it takes 2 hours to bath, dry and clip her. She's still as beautiful and to be honest she couldn't care less whether she is clipped, she prefers it to 3 hours standing on the grooming table.
It is a shame their coat changes, but many women post menopausal find their hair changes
but having lost 2 Cockers to pyometra and mammary tumours at a young age, I would still spay,but wait until they are have had a least 2 seasons