I agree with you that finding active users - and, more specifically, active readers, - is Steemit's biggest challenge right now. Without an extrinsic source of demand (like the Steemit account buying SP with funds used to sell advertising) it's going to struggle against the power law distribution of rewards to persuade people to power up.

Users might be satisfied with blogging-as-a-rewards-card if overall quality was obviously on an upwards trajectory, but curation is not working that well right now (more like a rich-get-richer scale-free-network than a meritocracy) and so, if you were judging by the trending page, you'd think that quality was going down not up.

Both Synero and Yours.network look like they could challenge Steem if those problems don't get ironed out.