You actually don't need to submit trash for higher than 30%. "Stock lists" usually make about 30%, and deviations usually get about 45-60%. Honestly, I like trying new things out in the arena. I prefer if my decks do well, but I don't really mind if they stay lower in the rankings, since the point is that they give people a fun time. For example, I not too long ago put up a nightmare-flying trident deck with flooding as the oracle card. It surprisingly got only 37.5% approval rating, but I know it was creative enough and it doesn't matter that it went from 10-2 to 16-8 in about a day since I can just put up a new deck. The ability to put up a new deck makes losses inconsequential, and the about 40 electrum per day I might make more isn't worth making a boring deck and decreasing the fun experience for all. Plus, some decks I make get enough to make 'more' than a standard deck would.
Besides, Arena is for silly things, like putting up a farm of 29 dead cards, 6 SoSa's, full stats, and seeing it get a 3-3 rating with 1 thumbs up.