With the audacity of the murders and the elusiveness of the murderer, it's tempting to think that the killer must have had some kind of inside track to always remain one step ahead of the law. Bear in mind that the other murders and attacks in Whitechapel at that time were unsolved, same goes for the Torso series. Crimes of this nature were not the bread and butter of the Victorian police force. Random, seemingly motiveless murders where the victims were selected by chance. They had little to no experience investigating serial killers, nor were they equipped with the modern forensic techniques to catch the perpetrator ex postfacto. Personally, I think like most serial killers, the Ripper had the right combination of low cunning and dumb luck to get away with it.
Hail to the king, baby!