"The record had everything a great disco record is supposed to have," wrote Peter Shapiro of "I Will Survive," and he was right. (Source)
The song certainly has all the musical elements of disco. Although no simple formula can narrow down what makes a disco song, the four-on-the-floor beat, the syncopated bass line, the orchestral backing (including a string section), the jazz and soul influences, the centrality of a diva's strong, and the lively voice make it a perfect blend of disco's defining elements. Taken all together, the song also achieves the "wall of sound" effect associated with many disco songs.
In a less technical sense, "I Will Survive" also captures the feel of disco. The song is relentlessly upbeat and joyously escapist, and hearing it is an experience that doesn't provide much of a break in the action. It's not hard to imagine dancing out your woes to this song over and over again without getting sick of it. Mostly because many of us have danced out our woes to this song over and over again—or is that just us?
The song certainly isn't for everyone, sure, but something about it makes us want to put on roller skates and sparkly green bellbottoms and wave our hair around like a girl in an iPod ad.
Disco saves!