Not true at all. I mean, somewhat true, but the lyrics can DEFINITELY help to make it an even bigger hit! Do you think The Final Countdown would get airplay ever new year's eve if it wasn't about "the final countdown" at all? Or White Christman if it was about something different? IML also was used for tons of sports events - again, the lyrical content DEFINITELY helped! People also have to be able to relate - at least in pop music (another aproach is going by attitude, which sold lots of grunge and sleaze-rock-records). Everyday had a worse melody and the lyrical content was recycled, so it's natural that it wasn't a big hit. But IML definitely wouldn't have been the hit it was if the lyrics would've been like the ones of Hey God or Prostitute.