Quoted from drsfmd:
Americans have destroyed the breed by breeding for “low slung” hips as the cornerstone of the standard and leading to too many dogs with dysplasia that are effectively crippled. Buy from a breeder in Europe and avoid the US bloodlines altogether.
There are still some breeders in the US that do not go that route. However, you are 100% correct with respect to the gross exaggeration of form by many. You'll see pics of ones where one of the back legs is bent at over 90 degrees at the hock and the hock on the other leg is touching the ground. Here is an article on the four types:
Unfortunately, this fate has not been limited to the German Shepherd. There are a number of other breeds where this has occurred to the point that the breed is not able to perform the function as intended (or at the level intended) and/or you have subtypes like the article above notes. For example, there are field and bench Springer Spaniels. The beautiful, silky, long flowing coats of the bench 'style' would be a nightmare in the field.