I agree with you - for the most part: Success on Steemit is part luck - leaving a comment at this post and not that and so coming to the attention of X and not Y. But for the most part it is simply hard work, persistence, stamina. And it seems investing early helps too, like you said. As soon as I had "worked off" the 15 SP delegation I bought nearly 80 Steem. Not much, but it made life on the platform so much easier. Maybe some bigger accounts took that as a sign that I was serious about Steemit?
A lot of those "shunned" by other social media I could live well without - but that's what "mute" is for, right? But as shocked as I am about the posts of some people ("How can someone with the brain to form a full sentence believe that?"), as adamant I am about their right to post their believes - as long as they don't use abusive language etc. If someone wants to be taken seriously they have to take the others seriously, too.