You could also look at it like this - you bring followers from other platforms and suddenly you have many more SteemIT followers and your earnings rise from that. There is no need for an affiliate program. Build your audience organically and you'll be fine.
Why should there be a need for referrals ? We earn by posting so that's incentive enough. Or stay on other channels and earn nothing for posting ! In my mind there's only one way. Create good stuff and keep at it. Do that enough and it will happen.
I think there's probably too many people on here who thought this was a get-rich-quick method and become frustrated when they quickly find out it isn't. Not for one second saying I think that about you, but you can sense a lot of frustration in newbies who post reasonable content and earn nothing when there's lots of average/boring content that's banking big.
Wish you all the best. Following.