Well, you have to take in consideration that most people search the audio portal for tracks that can be included in their projects. Not only for the listening pleasure. While a specific type of genre/songs fit an animation/movie/game better, some don't. Actually the audio portal was created for the sole purpose of making people get royalty-free music that can be used in their games/animations.
That aside, a problem of the audio portal is probably that people can vote daily on a song, including yourself. If you've got 5 friends who vote 5 daily, you'll see your song in the tops someday. Either that or the songs just fit in an animation/game of someone.
I don't intend to make you stop submitting to newgrounds. If your songs are good or fit in animations/games people will use and vote on them for sure. Everything else was said by the comment above me.
Good luck for future works.
PIED3
It would be silly to stop submitting stuff here just because the people who you like aren't getting the attention you feel they deserve. Just remember that music is completely subjective and just because someone perhaps did spend 30 mins on FL studio doesn't mean that they've made a "bad" song. They've made a song perhaps you don't like, but you've got to face the fact other people do. It's not very sensible to make music that just tries to appeal to the masses, i assume that's why you've come to newgrounds in the first place :P