It gives me a fuckin' headache, is what it does. :laugh:
Sorry, but that logic fails when you think using the "Temporal Mechanics" that Kagami mentioned. If what you said were true, then the belt would have disappeared at the EXACT same time that future Tendou disappeared. Future Tendou disappeared because by giving his younger self the belt, he changed the outcome in the future and he (the way that he grew up) no longer exists. By changing the past, EVERYTHING from that future would no longer exist, future Tendou, the belt he gave to his younger self, the movie riders, the satellite, everything would be gone, and they would all disappear at the same time, not one at a time the way you suggested. The fact is, the belt actually remains and young Tendou is able to use it. Without the belt, young Tendou would not have been able to escape from all that rubble that he was pinned under. He wouldn't have been able to save Hiyori from the rubble the way he does at the end of the movie.
In the series, during the scene where we see young Tendou get the belt, we also see that he was not pinned by lots of rubble the way he was in the movie. We see him walking over to the Native that imitated his father, who then gives him the belt. The two scenes are totally different, the scenarios were different, the source of the belt in the two scenes are different. This is because the series and the movie are not connected in that manner. The movie is set in an Alternate Universe setting and has no bearing/influence on the events of the series whatsoever.
The KR movies have always been set in an Alternate Universe, so that they can do stuff there that they cannot do in the series, either for financial reasons, or because they don't want to **** up the storyline/canon that has already been established. TV TOEI (the company that produces both the series and the movies) have consistently maintained this fact and when asked, have repeatedly said, on numerous occaissions that the movies are written to be completely separate from the series and that the two (in terms of storyline/canon) are not meant to actually have any literal connection. The movies are a "What if?" type of story. In this case: What if the meteorite that had orginally crashed in Shibuya was actually just a fragment of a much larger one? What if, instead of that smaller one, the much larger one actually crashed into the earth? What if Yaguruma never had "Kanzen Chowa"? What if he didn't lose "TheBee"? What if Kagami hooked up with Hiyori? What if Hiyori wasn't so emo? What if there was no Juka??? :sly:
In a way, setting the movies in an Alternate Universe allows the writers to explore other potential storylines/arcs that they otherwise could not have done for the series.