Only orthopedic or rheumatologist if hypermobile joints continue to loosen, different parts of affected joint's cartilege wear down? Why or why not?
Usually not. In some cases wear will happen...Notably subluxing shoulders and kneecaps. However in most cases only risks are of other issues like worsening instability if repetitive minor injury such as recurrent shoulder or patella dislocations . Most "loose joints" cause no symptoms or symptoms lessen with time.