The Amazon case is an interesting one because, despite the appeal of the OP's argument, one can hardly deny the success of Amazon's product listings in spite of their ugly URLs.
However, this raises up an important consequence of clean URL design: when you're offering things that may be classified in several categories, it requires good design on the backed/framework to make sure your URL taxonomy isn't overly constricting. For example, example.com/toys/Nintendo-wii or example.com/consoles/Nintendo-wii?
Either one is legit but creating and keeping consistent taxonomy is difficult enough on its own without worrying simultaneously what the URL looks like
However, this raises up an important consequence of clean URL design: when you're offering things that may be classified in several categories, it requires good design on the backed/framework to make sure your URL taxonomy isn't overly constricting. For example, example.com/toys/Nintendo-wii or example.com/consoles/Nintendo-wii?
Either one is legit but creating and keeping consistent taxonomy is difficult enough on its own without worrying simultaneously what the URL looks like