Audio problem: Just before Toby closes his bedroom door while Roy and Ronnie are arguing, if you listen carefully you can faintly hear director Steven Spielberg telling him to close the door. (01:05:00)
Audio problem: When Gillian is in the forest looking for Barry, at one point she can be seen mouthing Barry's name, but there's no audio.
Audio problem: In the scene just as Roy, Gillian, and Larry take off for Devil's Tower, the army officer is on his car phone speaking to his superior. When his superior tells him if they don't get Roy and company off the mountain in one hour, to use EZ4. Lacombe, who was talking to David at the time, looks at the officer and says, "What's EZ4?". Lacombe should not have known what was said over the phone, as only the officer and we, the audience, knew what was being said. It wasn't a speaker-phone. [The army officer was using a VRC(vehicle radio console.) Not a cellular phone. The radio has a speaker mounted on the front of the console in addition to the speaker in the handset. So everyone would be able to hear the conversation on the radio. ].






Answer: Devil's Tower really is out in the middle of nowhere, and in one of the least populated states (it's "only" 90 miles away from Mt. Rushmore, but it's an incredibly boring 90 miles of mostly empty plains) so it didn't make for a convenient tourist attraction like other landmarks and thus didn't garner as much fame (it's actually much more famous nowadays, thanks to this movie). That said, the movie seems to have cleverly provided two separate "reveals" for this plot turn: those familiar with Devil's Tower will recognize it when Richard Dreyfuss knocks the top off his sculpture, giving it the distinctive "flat top" shape; then, only minutes later the rest of the audience will discover it along with the characters during the news broadcast. It wouldn't surprise me at all if this was set up deliberately keeping in mind the landmark's status of "kind of famous but not really THAT famous."
TonyPH
Your explanation (and the other answer) helps makes the overall plot more understandable. The French scientist, Lacombe, mentions that there were probably hundreds of people who were implanted with the Devil's Tower image in their minds. As pointed out, it is not a particularly recognizable landmark, which would explain why many never made the connection to it.
raywest ★