A tacky mess: the masses vs. great design
Left to its own devices, the mob will augment, accessorize, spam, degrade and noisify whatever they have access to, until it loses beauty and function and becomes something else.
The tragedy of the design commons.
A farmer's market with no entry requirements turns into a bazaar and then into a souvenir stand and finally into a flea market.
A bulletin board with no moderator or hierarchy becomes a random mess of affiliate posts and noise, where only a smart search engine is helpful.
An Apple product designed with user feedback would have thousands of extra features, multiple input methods and weigh 18 pounds.
(The best exception to this rule are some--not all--places where people live, including parts of Manhattan and Kibera, Kenya. But even in the best instances, as soon as commercial interests are served, it starts to fail).
It seems democratic and non-elitist to set it and forget it and let the users take over. But the tools we use (Wikipedia) and the brands we covet (Nike or Ducati) resolutely refuse to become democracies.