Part of it may be the same reason that developers love to rewrite code: all creative works over a certain age accumulate compromises, and newcomers don't unders

Part of it may be the same reason that developers love to rewrite code: all creative works over a certain age accumulate compromises, and newcomers don't understand the reason for those compromises. So a new set of designers, like a new set of developers, feel compelled to "rationalise" what they've inherited. Sometimes they succeed, and build a much more logical information architecture... but many times the new design succumbs to the same entropy that that the original one did.