People who actually enjoy using steemit are far and few between. That is the main issue. Most people just use it as a personal piggy bank, or view it as potential one, and personal circumstance and faith in the system varies so they're apt to crack it open at different times.

Scale also plays a large role in this, when a few accounts have power orders of magnitude above everyone else then people justifiably tell themselves it's pointless to invest in or try to influence a system that is so stacked against anyone with less than hundreds of thousands or millions of SP. Also, just like corporations and economies of scale, you reduce friction when you have so much of a resource to expend and reinvest or sell off, whereas many are not in a position to do so and do not have a stake to begin with and accumulating SP is a trying task if income is so intermittent and disconnected from the levels of effort they put in, especially when so much of the latent VP goes to bots or circles.

Basically, until you can prove otherwise, most will smell that the platform reeks of a scam, and will have no interest in truly participating in full, even if they temporarily give it a shot to see if they too can profit from it.

Also, the way that voting works on steemit is very anti-social to begin with.