I most likely won't be able to give a definitive answer - it can be impossible to say for sure what makes a song a hit and there isn't always a correlation between a song being a hit and it sticking around in the collective zeitgeist either , but I can make a few educated guesses.

First off, you may not have heard Apache by Sugar Hill Gang as often as you think. (On the flip side of that, you've probably heard part of the song sampled more times than you realize).

The song had two versions released to varying degrees of success in Europe. Here's one of the first cover versions, by a group called The Shadows, which went to #1 in the UK and Ireland and charted in other European countries as well.

In the 1973, The Incredible Bongo Band released their version, which is the version that has kept the song famous. Not because their version became a smash hit, but because according to whosampled.com the IBB version has been used as a sample over 700 times, by artists including Jay-Z, Kanye, Grandmaster Flash, Missy Elliott and The Beastie Boys, not to mention the Sugarhill Gang version. The Sugarhill Gang version didn't fly completely under the radar either- it made the Hot 100, but didn't crack the top 50, and made it to #13 on the R&B charts, which, at the time it was released were probably a better gauge of whether or not people were listening to a Hip Hop song than the Hot 100 - Rap was still a novelty on the pop charts at that time even though some songs broke through (This was only a few years after The Sugarhill Gang's own Rapper's Delight introduced the music form to a wide audience at all), it wasn't (and still isn't) what most people would have thought of if you mentioned the sound of 1980s popular music.

Amongst 700+ tracks sampling the song, when you hear Apache, why do you think of Sugarhill Gang? They certainly aren't the most famous artists to have used it, and other artists have even had bigger hits using the song (including at least 1 number 1 hit by C+C Music Factory.

How did one version of a song from the R&B charts (That may have still gotten played at dance clubs, but setlists from 40 year old club nights are a little thin on the ground, so who really knows?) break into the popular consciousness and become associated with the Sugarhill Gang more than the original artist, or even the cover version they sampled? Well, in 1995, the song's Life got flipped and turned upside down, when it was featured on The Fresh Prince of Bel-Air, which not only exposed it to an audience much wider than that of 80s hip hop fans, but in the form of reruns, quite probably continued introducing it to people who never watched the original show - or have even heard of the Sugarhill Gang.

Sources Consulted: (In Addition to those linked in Text)

Hip Hop Family Tree by Ed Piskor