The Adventures of Sherlock Holmes: (in 1890)

I think that there are many reasons why the story is greatly effected by the time period it takes place in. One reason is because of technology. They didn't have quite as sophisticated technology that could be used for crime-solving purposes back then. No DNA tests, no security cameras, and no cell phones to alert nearby officers. Today, a criminal simply wouldn't have been able to break into a bank quite as easily as the pawnbroker's assistant did in "The Red-Headed League". Depending on how the land that buildings were built on was back then, someone may or may not have been able to break in through a bank floor, but these days, It wouldn't be that easy, you would have to dig for at least a few weeks, and even if the floor of the bank was made of dirt, there would still be security systems.
Besides the fact that security was less sophisticated back in the late 1800's, it also seemed like you could get away with things a whole lot easier. In "A Scandal in Bohemia", Holmes instructs Dr. Watson to throw a smoke bomb in the window of Irene Adler's house, and gets away with it as if nothing happened. Didn't somebody see him? These days you would surely get arrested, and sent to jail for one reason or another, even if you did help solve a crime. Due to these reasons and several others as well, I conclude that the time period made a huge impact on crime, which provided a much needed use for an intelligent detective like Sherlock Holmes.