One should simply approach the matter objectively. If the film had grossed $500 million ++ at the box office, there would not be this discussion about whether the film had earned its costs. With everything that is below, you can only speak on flop is finally the topic here in the thread.
I would have liked a better film and at least $ 700 Mill ++. But the film does not give that. It is only on old known formulas and nothing in the film makes you keen on a second part.
If one had roughly said Peter Jackson with a 3 part Drizzt saga in the boat, with a team that likes fantasy or something with Bruenor and Klauth/ Icing death similar turned, what also normal people picked up and not only nerds, then that would have given a boost with identification for D&D.
But what did we get, a sack of potato jokes, a nice villain, etc. I'm not even talking about dragons. Close behind and before a few little stories about the movie just won't do. Do you want to make the really big deal you have to risk something, the tame attempt of HAT was just nice meant, but honestly if the production costs come back, you can be happy.
My kids thought the movie was ok, but we also saw Excalibur from 1981 on the big screen a week later and they loved it.