Randomness plays a factor in everything, but there's a HUGE difference between "slightly affected by random chance" and "lottery."
We're already talking about 20% of "not illiterate" novels getting accepted. That's a huge number. Considering that "not illiterate" includes bad, mediocre, good, and great novels, and they obviously don't have the same chance of getting published, it's extremely reassuring.
Analogy:
You're trying out for a basketball team. There are a hundred people there, and there are only two positions. Sounds like it's a crap shoot, right? It would be, if all hundred people were roughly equal. But it's not.
Ninety of those people have not only never played basketball before, but they aren't even in good physical shape. Many of them think they're awesome, though.
Some unknown number of the others have played basketball, but they're lazier than you, and/or they won't listen when the coach tries to teach them better techniques. You'll probably easily beat them as well, so you don't even have to worry. You just need to pay attention to other players who work as hard as you and listened to their coaches. How many people will that be, really? Maybe 3-4 total, including you. Maybe even only two, guaranteeing you a spot.
So, you are really only competing with a tiny number of people for the top two spots. Your chances are very good.
(In other words, 90% of submissions are worthless crap and some unknown but high percentage of the remainder are boring, lazily written, or written by people who won't take advice. If you're a serious writer, you don't have any business being in either of those categories. Serious writers are probably in the top 5% at least, and the top 2% get published. That's some good odds.*)
*Of course, we don't know how accurate the 90% and 2% figures really are. We don't know how much they vary by genre, by the economy, etc. If your passion is historical fiction that's not romance, you're probably going to have a much harder time getting published than average, for example.