"Could that be the reason why some posts do worse?"
I would say, probably not. There are simply so many variables. The most likely explanations for most people, when they ask this, is they are:
- Not networking
- Not posting high enough quality
- Haven't been persistent enough
- Have unrealistically high expectations
"How are they doing this? If there is a secret to success (besides all the other recommendations I'm already following) please share =)"
Ask, and ye shall receive.
Thank you, @lexiconical =)