Why do you keep this thing going?
Why do we keep an original copy of the Constitution and Declaration of Independence? Paper isn't meant to last hundreds of years, so there is a fair bit of money and effort put into maintaining the conditions necessary to prevent them decomposing. The originals serve no purpose in the presence of thousands (millions?) of reproductions, so why bother? These documents are a tangible reminder of history. They link us to our origins and provide us some common culture. You don't dismiss the Declaration a longform tantrum; it's the righteous indignation of our founding fathers.
The founding of nations wasn't done with documents in 927 A.D. Great Britain has no Declaration or Constitution to preserve. They have a royal bloodline to connect them to the founding of their nation. To dismiss it so blithely is to imply that the nation's living history is not worth the effort to preserve, and that's quite a slap in the face, considering what Britain is and has been.