There is much in your post that - hopefully - would catch someone's attention; here's just one sentence that caught mine:
Engagement is personal.
Sincerity comes through when one engages with others, as does insincerity.
Taking the time to truly read (not skim) what another has taken the time to write; taking the time to ponder over a person's work, to appreciate more fully whatever humor or poignancy or nuance or depth it offers; taking the time to craft a thoughtful response (not dash off a superficial note): these are marks of giving of oneself, as much as the writing or photographs or drawings or paintings or music or videos are the manifestations of the creative's giving of himself/herself/themself.
It's possible to fake sincere engagement for a while, in an attempt to gain some external rewards, but that's an awful lot of effort, over an awfully long time, for it to "pay off," and I daresay that problem takes care of itself.
To truly and personally engage is to give of one's time, a most valuable and fleeting asset. Whom we choose to engage with, and the care with which we do so, are reflections of what we consider important. That kind of engagement is its own reward.
This is a vital factor in my opinion too - sincerity and authenticity. There are plenty who engage for the reward, others who do it to troll - at the end of the day, it is those who are decent humans that do the best.
Just like in a relationship started on fake interests and promises, eventually, everyone leaks. If you have to hide yourself behind a mask of sincerity, what leaks out? :D
I agree. I give people a lot of my time, I give a few people none of it - after having too much wasted and taken for granted.
Thanks for taking your time :)