Rewards are always a problem because they convey votes and influence content. It's like this everywhere, steemit, youtube, blogs, it's clear that when you expect a profit, things change. As far as quality is concerned, it is difficult to decide to give your content to steemit with steemexclusive and then be recognized for just a few cents. So sometimes it's easier to participate in a contest without giving too much of your ability. I love drawing, but it takes me hours to finish a drawing, and I only publish it in contests because every time I published it spontaneously it went ignored and it's like that for everyone. Furthermore, there is content that is not particularly interesting and is compensated with a lot of money and this is also noticed by newcomers, as in all social networks those who are better at networking and finding friends have more votes, but this is not necessarily linked to the quality of content. I have seen the exact same mechanism in many platforms, steemit is no exception.
I think that a lot of your thoughts support how I perceive these contests, in particular:
Whereas I want to see the ability and I'll return to those who like to share their ability (assuming it's something I'm interested in) over and over again.
All of this, my post, the replies, Steemit in general comes down to this simple statement:
People come to Steemit expecting a profit and their behaviour is driven by this sole goal whereas...
...is true. What comes through from these users though, is that desire to network, to make friends, to be genuine and not solely driven by money (which is an added bonus). They're there supporting others so when they share something, this support is reciprocated and "we" lift each other. A real community.