A lot of it was down to Dino Di Laurentiis (producer) being peeved that he let Silence Of The Lambs get away. He was the producer of Manhunter, which did diddly squat at the cinemas upon its original release. He decided to retitle the film Manhunter rather than Red Dragon, because he didn't want people to associate it with the millions of kung fu and karate movies which were being released by Chuck Norris and his frienRAB at that time.
Because Manhunter did so poorly when it was released at the cinema, Di Laurentiis (and his production company DEG) turned down the opportunity to make The Silence Of The Lambs movie. So, it was produced by Kenneth Utt, Edward Saxon and Ron Bozman for Orion films - and went on to be the biggest movie that that production company had ever released, and they also had video rights for it when it came out on tape after its cinema release.
So, when Hannibal was up for grabs, De Laurentiis decided he wasn't going to let Hannibal Lecter get away from him again. So, he produced it and his production company made the movie - and again, it flopped. But not as big a flop as Manhunter - mainly because it starred a lot of the same cast as were in Silence Of The Lambs - particularly Anthony Hopkins.
So, this time De Laurentiis decided he was going to remake Manhunter but with Hopkins as Lecter - as far as he was concerned Hopkins was Lecter, and Manhunter (or Red Dragon) would have been as big as Silence Of The Lambs was on its original release if it had starred Hopkins instead of Brian Cox. He also admired the Gothic style of the Baltimore cells that Lecter was kept in compared to his own clinical white modern building that was used in Manhunter, and wanted to use this same style for the Red Dragon remake.
So, he remade Manhunter, but this time using the actor that people associated with Lecter (plus other actors from Silence Of The Lambs to play consistent characters such as Dr Chilton and Barnie), using the style of the penitentiary that people associated with Lecter, and using the original title of the book (as there aren't anything like as many straight-to-video martial arts movies being made nowadays as there were in the mid-eighties).
And surprise, surprise - again it flopped. The film wasn't even as big a cinema release as Hannibal - but at least it made him a lot more money than Manhunter did. But many, many people still prefer Manhunter to Red Dragon, because at least Manhunter was new when it was released, whereas Red Dragon is just churning out the same story with different actors, and a lot of people don't like remakes.