some don't know the xs11 shafts break clean-off at the threaded shaft on the back of the middle-drive, drive-shaft flails around then jams lock-solid, handy not to be mid-corner during. and shlt happens when the chain is loose and neglected etc.
chain instead of shaft, longevity is no problem 70's chains and sprockets maybe, modern way different 40,000 + kilometres and barely polished, not even close to worn, need to be a greenland shark to worry about it, shafts way better for non-mechanical types who prefer not have adjust the rear axle twice a year, not to mention pissing around with grimy rags, chain-wax etc..
