I think that a lot of your thoughts support how I perceive these contests, in particular:

it's easier to participate in a contest without giving too much of your ability.

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:

it's clear that when you expect a profit, things change

People come to Steemit expecting a profit and their behaviour is driven by this sole goal whereas...

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

...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.