I didn't read the 80 pages, but I have a question and this seems like the place for it.
What are the known variables contributing to the movie's financial under-performance?
Everyone I know liked the movie. This makes me think that variables other than quality were involved.(1)
What other new releases was it competing with?
Were other world events influencing the number of people watching movies during its release?
What other factors can go into poor performance at the box office that don't actually reflect on a movie itself--and were any of them present for this one?
(1) I'm not discounting a bias towards association with people who would like a well-made D&D movie, but I don't want to just assume that's the whole answer.
Reasons I've seen for people who didn't go are things such as... (whether really pertinent or not)
From Players (trying to put it in order of how many said it from most to least)
-Still Angry about the entire OSR thing
-Doesn't represent their type of D&D
-Will wait for it to come out on Streaming
-Will wait until it is free on streaming
-Looks like it isn't serious enough (too much of a comedy)
-Actors are not hot enough (yes, someone said this...)
-Not enough time
From non-players (sometimes family of players)
-Why should I watch it?
-I'm not interested in that type of stuff
-It looks stupid. Maybe if it were like LotR or GoT, but that looks like a poor copy of Marvel
-What is it supposed to be?
-I'll just wait for it to come to streaming
-I have other things I would like to do instead.
Most of this is obviously anecdotal, but combining a lot of those probably resulted in many reasons why it didn't have as many people watch it as may have if other paths of advertising or promotion had occurred.