I think Norvig's actually improved substantially since he wrote this — he wasn't at the peak of his career! But yes, it's a masterpiece, and yes, it's okay to not ever rise to that level, because even if nothing you ever create is as worthwhile as this, it's still worthwhile. Hacking is fun! And sometimes very useful, too.

(Also note that, despite appearances, this isn't the work of one man. Norvig didn't design Python and didn't invent the tabling technique for speeding up search; and Darius found a couple of bugs in the code. That doesn't mean it's not an authentic Norvig masterpiece.)