Thank you, @denmarkguy

Do all social network users seek rewards?

My theory is that all users of any social network seek rewards, overtly or covertly.

Covert rewards

Till Steemit, the social networks rewarded users covertly by taking their users on one big ego joyride. The rewards system is covert & opaque. As long as the social can enhance narcissistic behaviour, they can focus on "monetizing" users, incuding content providers, without compensating them in cash or kind. e.g. Facebook ramps it up by enhancing Facebook likes to Facebook reactions.
I've succumbed to coveting the enagagement that my youngest daughter gets on anything that she posts on Instagram, even in private mode.
On LinkedIn, the professional network, how many people have read my article there?
The social networks having caught on very early, have ridden the wave of users getting an ego kick out of the system. For users, the next step is to "game' it as you say. In another context, pertaining to peer approval Nassim Nicolas Taleb covers this is great detail. So the cat & mouse game ensues.

Overt rewards

Steemit, on the other hand transparently rewards content authors & creators. This is broadcast upfront.
Yes, you're right , @denmarkguy there wil be gamers.