That would only be true if votes were a limited resource. There's no real "competition" here. Something good getting upvoted doesn't stop absolute trash from getting upvoted. donio posting something incredible wouldn't mean it would offset something awful; it would just slightly change the timeslot of the awful thing.
Articles that go deep into technical subjects generally stay on the front page for half of the time of trendy lightweight posts.
Articles that go deep into technical subjects generally stay on the front page for half of the time of trendy lightweight posts.