Great post with so many things to consider. For the reasons you stated above, I never engaged in Facebook/Twitter/Instagram networks. Steemit feels different, as the impression I got when I first heard about it was that quality matters and I hope this holds true for the long-term future too.
In my opinion, it is a matter of expectations and self-reflection. I never considered that an online social network is the proper place to validate myself and gain self-esteem. It is a great tool to get in touch with like-minded individuals, to get inspiration and learn new things, but that's all -- I would never go as far as putting all my hopes and expectations there.