The obvious reason is every single document you publish is a liability and potentially a burden. At minimum, it is a cognitive burden and additional responsibil

The obvious reason is every single document you publish is a liability and potentially a burden. At minimum, it is a cognitive burden and additional responsibility. If it weren't a liability, why bother killing the links? If it weren't a cognitive burden, how could they have forgotten to keep the old URL structure in place? Everything is temporary. Archive what you care about if you really need it to last.